I did think about converting one of the other TL-01 trucks to become the downgeared version, but on the other hand I really like them as they are and don't particularly want to change any of them. My spare parts box is/was pretty full though, so I think it is probably best to use all of this stuff up and build a fourth truck. I bought a couple of spare chassis along the way, one was empty of mechanical parts and the other was a fairly rare lightweight (grey plastic) touring car chassis, which I sold on minus its nicely hopped-up internals for more than I paid for it.
Anyway, here's my kit of spare parts:
The first spare chassis got used to replace the one on Blue truck after it got cracked when it collided with the triangular base bar of a park picnic table which was hidden in long grass (the bar not the table!). The chassis I've used to try out this modification is the only spare I've now got and is unfortunately the cracked one. I've tried to repair it once already with chemical (epoxy) metal but this proved not to be strong enough. I'm now going to have to make some sort of metal shoe to reinforce this area, which is where the front arms attach. I've highlighted the cracks, which are in different places on each side, with a red CD writing pen. The ink from these tends to draw itself into the cracks making them easier to see:
An evening's work has got me this far. I've locked the differentials with hot glue, and have used bronze bushings to replace the plastic originals throughout the gearboxes and driveline. I couldn't really see the point of going for expensive bearings here, being as this truck won't need any advantages that these can give. Besides which it's likely to get pretty wet and muddy at some point, which would probably wreck them anyway.
I've used black screws everywhere they are visible just to keep things as tidy as possible. The pinion gear isn't here yet so I can't yet fit the new gearbox - the next stage will now be to get all the electrics fitted.
Wednesday, 22 February 2012
Tuesday, 21 February 2012
Gearing down a TL-01 (Part 3)
The only other thing I'm actually going to need to buy for this conversion is a 23 tooth motor pinion gear. I already have a 'speed tuned' gear set here, which came with a complete chassis I bought some time ago for a tenner.
Obtaining a 23t pinion gear is not difficult if I wanted to use standard Tamiya parts, but there are a couple of downsides to this choice. The first of these is the fact that Tamiya 'AV' pinions are made of a very soft aluminium, and this means that they wear out quite quickly. I've used up several in my three TL-01 trucks over the past few years, they last reasonably well with standard 'silver can' motors but cannot really take the power of a tuned motor. They tend to wear their teeth to sharp points, and make increasing amounts of noise as they do so (also noticeable if you manually push the car backwards). They also leave grey alumimium oxide residue, which is itself abrasive, on the other (plastic) gears in the rear gearbox.
The second downside is that you have to purchase them in pairs with a one-tooth difference between them, and one out of each pair does not fit a TL-01. Therefore you have to pay extra for something you are not ever going to use.
Here are the part numbers for each of the sets that contain one gear that will fit a TL-01 (options - 19, 21 and 23t):
Tamiya 50355, 18T & 19T AV Pinion Gear Set
Tamiya 50356, 20T & 21T AV Pinion Gear Set
Tamiya 50357, 22T & 23T AV Pinion Gear Set
It must be noted that Tamiya refer to the pitch of these gears as METRIC 48 pitch, which is not the same as a regular IMPERIAL 48dp (diametric pitch) gear.
This 'AV' size was used in Manta Ray, Group C, TL01, TB01, Wild Dagger, Detonator, Vanquish, Avante2001 etc.
In reality these Tamiya gears are metric 0.6 module pitch, which do NOT mesh correctly with normal 48dp pitch gears. My understanding, having read a fair number of RC forum posts, is that 0.6 mod equates to 42 pitch, and that GPM aluminium spur gears for a TL-01 are advertised as being this size.
(For reference 48dp - imperial diametric pitch = 48 teeth on a 1-inch diameter gear, 64 pitch = 64 teeth etc.)
I cannot find any reference to Tamiya clarifying this issue - their official answer is to "only buy Tamiya pinions"!
Now to the Tamiya TL01 Speed-Tuned Gear Set (#53342 or OP-342):
These are moulded in black plastic, to easily discern them from the standard (off-white coloured) version.
Also for reference, here are the Final Drive Ratios (FDRs) for each fitable size pinion, and again for each size when used with the Speed Tuned gearset.
Pinion Gear..... Normal Ratio...... Speed-tuned Ratio
19T ................. 7.96 ................. 5.95
21T ................. 7.20 ................. 5.39
23T ................. 6.57 ................. 4.92
This is the pinion gear I've chosen to use. It is intended for use in a Maverick Strada TC/MT/XT/XB series car/truck/truggy/buggy. Its part number and description are MV22081 MOTOR GEAR 23T 0.6 MODULE:
£3.53 + £0.89 postage & packaging.
UPDATE:
You can forget all I wrote at the start of this post about needing to buy a 23t pinion. I didn't. As I realised when I came to put the gearbox into the truck the mounting holes on the gearbox (to the truck) are not diametically opposite in relation to the output shaft.
This means that a 23t pinion will not fit, even though the gearbox is fitted to the truck on the 23t mounting holes. Actually, the difference in the offset is almost exactly equivalent to four teeth on the motor pinion. So a 19 tooth pinion DOES fit here instead. And being as I already had at least one spare 19t here anyway I had no need to buy anything new (beyond the gearbox itself) at all.
Anyway I hope the following makes things a bit clearer. If you use a rule on the gearbox lining up the mounting holes (this only works on one side!) it also just touches the output shaft as a near-perfect tangent, whereas the imaginary correct line should have passed centrally hole to shaft to hole.
Obtaining a 23t pinion gear is not difficult if I wanted to use standard Tamiya parts, but there are a couple of downsides to this choice. The first of these is the fact that Tamiya 'AV' pinions are made of a very soft aluminium, and this means that they wear out quite quickly. I've used up several in my three TL-01 trucks over the past few years, they last reasonably well with standard 'silver can' motors but cannot really take the power of a tuned motor. They tend to wear their teeth to sharp points, and make increasing amounts of noise as they do so (also noticeable if you manually push the car backwards). They also leave grey alumimium oxide residue, which is itself abrasive, on the other (plastic) gears in the rear gearbox.
The second downside is that you have to purchase them in pairs with a one-tooth difference between them, and one out of each pair does not fit a TL-01. Therefore you have to pay extra for something you are not ever going to use.
Here are the part numbers for each of the sets that contain one gear that will fit a TL-01 (options - 19, 21 and 23t):
Tamiya 50355, 18T & 19T AV Pinion Gear Set
Tamiya 50356, 20T & 21T AV Pinion Gear Set
Tamiya 50357, 22T & 23T AV Pinion Gear Set
It must be noted that Tamiya refer to the pitch of these gears as METRIC 48 pitch, which is not the same as a regular IMPERIAL 48dp (diametric pitch) gear.
This 'AV' size was used in Manta Ray, Group C, TL01, TB01, Wild Dagger, Detonator, Vanquish, Avante2001 etc.
In reality these Tamiya gears are metric 0.6 module pitch, which do NOT mesh correctly with normal 48dp pitch gears. My understanding, having read a fair number of RC forum posts, is that 0.6 mod equates to 42 pitch, and that GPM aluminium spur gears for a TL-01 are advertised as being this size.
(For reference 48dp - imperial diametric pitch = 48 teeth on a 1-inch diameter gear, 64 pitch = 64 teeth etc.)
I cannot find any reference to Tamiya clarifying this issue - their official answer is to "only buy Tamiya pinions"!
Now to the Tamiya TL01 Speed-Tuned Gear Set (#53342 or OP-342):
These are moulded in black plastic, to easily discern them from the standard (off-white coloured) version.
Also for reference, here are the Final Drive Ratios (FDRs) for each fitable size pinion, and again for each size when used with the Speed Tuned gearset.
Pinion Gear..... Normal Ratio...... Speed-tuned Ratio
19T ................. 7.96 ................. 5.95
21T ................. 7.20 ................. 5.39
23T ................. 6.57 ................. 4.92
This is the pinion gear I've chosen to use. It is intended for use in a Maverick Strada TC/MT/XT/XB series car/truck/truggy/buggy. Its part number and description are MV22081 MOTOR GEAR 23T 0.6 MODULE:
£3.53 + £0.89 postage & packaging.
UPDATE:
You can forget all I wrote at the start of this post about needing to buy a 23t pinion. I didn't. As I realised when I came to put the gearbox into the truck the mounting holes on the gearbox (to the truck) are not diametically opposite in relation to the output shaft.
This means that a 23t pinion will not fit, even though the gearbox is fitted to the truck on the 23t mounting holes. Actually, the difference in the offset is almost exactly equivalent to four teeth on the motor pinion. So a 19 tooth pinion DOES fit here instead. And being as I already had at least one spare 19t here anyway I had no need to buy anything new (beyond the gearbox itself) at all.
Anyway I hope the following makes things a bit clearer. If you use a rule on the gearbox lining up the mounting holes (this only works on one side!) it also just touches the output shaft as a near-perfect tangent, whereas the imaginary correct line should have passed centrally hole to shaft to hole.
Sunday, 19 February 2012
Gearing down a TL-01 (Part 2)
OK. Starting at the end point. The first picture shows the HPI 87634 gearbox mounted into the Tamiya Tl-01 chassis, as fitted with the longer Baja King/Champ suspension arms and a 1.9" wheel and tyre, along with an attached Integy 35 turn lathe motor.
In order to obtain the best possible wheel torque for crawling and climbing
ability, the object of the exercise is to try to achieve an approximately 3.0/3.5 MPH (or good walking pace) top speed for the truck.
The gearbox is positioned to use the 23 tooth pinion option (and the chassis motor mounting holes to match) because the ratio of the gearbox is a rather large
7.4 to 1, and this would give excessive overall reduction with any of the smaller available (19t, 21t) pinion sizes. To achieve the best possible wheel speed for crawling and climbing use it is likely that a 'SPEED TUNED' internal gear set will also be required to additionally compensate for the gearbox's large reduction ratio.
This pinion choice has the distinct advantage of mounting the gearbox as far forwards as possible. This positioning means that it is necessary to remove a lesser amount of plastic material from the rear (left-side and smallest) part of the main chassis in order to fit the new additional gearbox. This rear (left) part is one-half of the rear main gearbox compartment, and it is far easier to re-make and reseal this area to prevent otherwise damaging foreign object ingress when less material is initially removed.
There is plenty of tyre/motor clearance, in fact more than is found on any TL-01 fitted with standard touring car suspension arms, these including the Stadium Raider and Ford Lightning trucks. The next three pictures show different views with the gearbox and motor fitted (N.B. the suspension arm has been reversed - this gives the longest possible wheelbase when using only standard parts):
The next three photos show inverted views. The gearbox smoothly protrudes below the bottom of the chassis by about 6mm (1/4").
An additional advantage of this mod is that a motor guard/heatsink will now fit around the completely exposed motor. Previously, when the motor was buried in the chassis, a full size heatsink would not fit.
Three more views, showing the gearbox alone in the chassis. In the last one daylight can just be seen past the box. In reality the box is quite a tight fit in there, and becomes in part a longitudinal structural member.
The chassis only requires cutting of the left hand side, which is ordinarily constructed in two parts, whereas the right hand side is a single piece and does not need any re-working. These next two pictures show the material removed from the lower part(s) of the motor area. The lower of the two little 'fins' above the motor protector mount has been trimmed back slightly just to avoid contact with the motor itself:
These last two pictures mainly show the amount of material removed from the front (left) chassis section. The rearmost upper and lower screw locations remain unaffected:
In order to obtain the best possible wheel torque for crawling and climbing
ability, the object of the exercise is to try to achieve an approximately 3.0/3.5 MPH (or good walking pace) top speed for the truck.
The gearbox is positioned to use the 23 tooth pinion option (and the chassis motor mounting holes to match) because the ratio of the gearbox is a rather large
7.4 to 1, and this would give excessive overall reduction with any of the smaller available (19t, 21t) pinion sizes. To achieve the best possible wheel speed for crawling and climbing use it is likely that a 'SPEED TUNED' internal gear set will also be required to additionally compensate for the gearbox's large reduction ratio.
This pinion choice has the distinct advantage of mounting the gearbox as far forwards as possible. This positioning means that it is necessary to remove a lesser amount of plastic material from the rear (left-side and smallest) part of the main chassis in order to fit the new additional gearbox. This rear (left) part is one-half of the rear main gearbox compartment, and it is far easier to re-make and reseal this area to prevent otherwise damaging foreign object ingress when less material is initially removed.
There is plenty of tyre/motor clearance, in fact more than is found on any TL-01 fitted with standard touring car suspension arms, these including the Stadium Raider and Ford Lightning trucks. The next three pictures show different views with the gearbox and motor fitted (N.B. the suspension arm has been reversed - this gives the longest possible wheelbase when using only standard parts):
The next three photos show inverted views. The gearbox smoothly protrudes below the bottom of the chassis by about 6mm (1/4").
An additional advantage of this mod is that a motor guard/heatsink will now fit around the completely exposed motor. Previously, when the motor was buried in the chassis, a full size heatsink would not fit.
Three more views, showing the gearbox alone in the chassis. In the last one daylight can just be seen past the box. In reality the box is quite a tight fit in there, and becomes in part a longitudinal structural member.
The chassis only requires cutting of the left hand side, which is ordinarily constructed in two parts, whereas the right hand side is a single piece and does not need any re-working. These next two pictures show the material removed from the lower part(s) of the motor area. The lower of the two little 'fins' above the motor protector mount has been trimmed back slightly just to avoid contact with the motor itself:
These last two pictures mainly show the amount of material removed from the front (left) chassis section. The rearmost upper and lower screw locations remain unaffected:
Tuesday, 14 February 2012
Gearing down a TL-01 (Part 1)
With having three Tamiya TL-01 based trucks in the collection ('Blue' 'Red/Yellow' and 'Army'), all of which get used in a variety of environments, it has not escaped my attention that these things are just a bit overgeared for certain styles of off-road running - i.e. going anywhere slowly. It stands to reason really, being as the chassis was originally designed for use in a touring car, and that it's not that difficult to get 40+mph out of a reasonably tuned example.
Not so good if you want to plod around in the woods though - running bigger tyres definitely works against you in this direction as well. Red/Yellow and Army both run the lowest possible gearing, via fitment of a 19 tooth motor pinion (out of a choice of 19, 21 or 23 teeth), but this still doesn't give me much stump-pulling torque. Blue is a litle bit different being as it's currently more of a fast street truck, running a 19 turn motor and a 21 tooth pinion.
On various RC forums I've read that others have managed to get a 16 tooth pinion to work in a TL-01 by drilling new motor mount holes in the correct positions to achieve proper meshing, although I haven't come across any photos showing how this was actually done. Whether plastic had to be removed from the rear gearbox portion of the chassis remains to be seen, but either way, the motor mounting had to be physically relocated in a generally rearwards direction. The change in gearing that this mod gives is simply 16/19 = 0.84210 - therefore a 15.7894% reduction (if my maths is correct).
OK. Change of subject for a few minutes.
Over the last few weeks there have been a huge amount of HPI RC spares appearing on eBay. These include those for Maverick Scout crawlers and HPI Wheely Kings. Of particular interest to me among these was a 87632 HPI WHEELY KING COMPLETE ROCK CRAWLER CONVERSION SET.
Normally retailing for RRP £127.99 and appearing on eBay for one penny less, these started appearing for £39.99 plus £3.95 postage. A quick search on the net found them available direct from Modelsports (in Otley, West Yorkshire) for £32 with £6 for courier delivery.
That's very nice buy I thought to myself. The tyres alone would normally be well over the asking price. And there's plenty more in there to keep my project bench active for quite some time to come! With the first few sets disappearing off eBay quite quickly I felt that I really had to get one before they all went, assuming that the discount is available only because of a temporary overstock situation. As it had happened, my Mum had given me £30 for a new pair of jeans as a Christmas present, I hadn't got them yet and now I'm still going to need to get a pair! Oh well, I guess I'm old enough (52) to choose my own presents!
Anyway, although you can't see it in the photo this kit also includes the #87634 Reduction Gear Box.
Fits Model > 102117 - RTR CRAWLER KING WITH JEEP® WRANGLER® RUBICON BODY
Part: REDUCTION GEAR BOX SET (WHEELY KING)
Description: Transform the Wheely King truck into a rock crawling beast with this Reduction Gear Box Set. This genuine HPI factory approved gear box bolts right into any Wheely King for a perfect fit. It contains a tough metal case, ball bearings and all-metal gears for extra durability. The gear ratio is transformed from 23:1 on the stock truck to a whopping 174:1 after the installation. This Reduction Gear Box Set is perfect for rock crawling because it delivers stump pulling torque and the power to climb any slope. Recommended for use with #87633 Wheely King Crawler Conversion Set, but it can also be used individually or as the basis for a custom project.
Part Category > Car > Car Spares & Options > Specific Car Spares & Options > Drivetrain
Part Number: 87634
Part Area: Drivetrain
Part Type: Optional / Hop Up / Racing
Weight (g): 82
Part Status: Current Part
(Current eBay price £17.32 + £0.99 Standard Delivery)
My first question concerning this lovely little gearbox, even before I'd ordered the kit, was - can one of these be fitted into a TL-01 chassis?
The answer I discovered last night, after two hours fairly fiddly work, is a reasonably qualified 'yes'.
(Being as the camera battery is flat right now and it needs an overnight in the charger, how I did this (first stage of another truck?) will now be the topic for the next post. Coming up ASAP.)
Not so good if you want to plod around in the woods though - running bigger tyres definitely works against you in this direction as well. Red/Yellow and Army both run the lowest possible gearing, via fitment of a 19 tooth motor pinion (out of a choice of 19, 21 or 23 teeth), but this still doesn't give me much stump-pulling torque. Blue is a litle bit different being as it's currently more of a fast street truck, running a 19 turn motor and a 21 tooth pinion.
On various RC forums I've read that others have managed to get a 16 tooth pinion to work in a TL-01 by drilling new motor mount holes in the correct positions to achieve proper meshing, although I haven't come across any photos showing how this was actually done. Whether plastic had to be removed from the rear gearbox portion of the chassis remains to be seen, but either way, the motor mounting had to be physically relocated in a generally rearwards direction. The change in gearing that this mod gives is simply 16/19 = 0.84210 - therefore a 15.7894% reduction (if my maths is correct).
OK. Change of subject for a few minutes.
Over the last few weeks there have been a huge amount of HPI RC spares appearing on eBay. These include those for Maverick Scout crawlers and HPI Wheely Kings. Of particular interest to me among these was a 87632 HPI WHEELY KING COMPLETE ROCK CRAWLER CONVERSION SET.
Normally retailing for RRP £127.99 and appearing on eBay for one penny less, these started appearing for £39.99 plus £3.95 postage. A quick search on the net found them available direct from Modelsports (in Otley, West Yorkshire) for £32 with £6 for courier delivery.
That's very nice buy I thought to myself. The tyres alone would normally be well over the asking price. And there's plenty more in there to keep my project bench active for quite some time to come! With the first few sets disappearing off eBay quite quickly I felt that I really had to get one before they all went, assuming that the discount is available only because of a temporary overstock situation. As it had happened, my Mum had given me £30 for a new pair of jeans as a Christmas present, I hadn't got them yet and now I'm still going to need to get a pair! Oh well, I guess I'm old enough (52) to choose my own presents!
Anyway, although you can't see it in the photo this kit also includes the #87634 Reduction Gear Box.
Fits Model > 102117 - RTR CRAWLER KING WITH JEEP® WRANGLER® RUBICON BODY
Part: REDUCTION GEAR BOX SET (WHEELY KING)
Description: Transform the Wheely King truck into a rock crawling beast with this Reduction Gear Box Set. This genuine HPI factory approved gear box bolts right into any Wheely King for a perfect fit. It contains a tough metal case, ball bearings and all-metal gears for extra durability. The gear ratio is transformed from 23:1 on the stock truck to a whopping 174:1 after the installation. This Reduction Gear Box Set is perfect for rock crawling because it delivers stump pulling torque and the power to climb any slope. Recommended for use with #87633 Wheely King Crawler Conversion Set, but it can also be used individually or as the basis for a custom project.
Part Category > Car > Car Spares & Options > Specific Car Spares & Options > Drivetrain
Part Number: 87634
Part Area: Drivetrain
Part Type: Optional / Hop Up / Racing
Weight (g): 82
Part Status: Current Part
(Current eBay price £17.32 + £0.99 Standard Delivery)
My first question concerning this lovely little gearbox, even before I'd ordered the kit, was - can one of these be fitted into a TL-01 chassis?
The answer I discovered last night, after two hours fairly fiddly work, is a reasonably qualified 'yes'.
(Being as the camera battery is flat right now and it needs an overnight in the charger, how I did this (first stage of another truck?) will now be the topic for the next post. Coming up ASAP.)
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