HPI Sprint 2 Mods
#766
Correcting the loose steering on a Sprint 2 isn't as hard, nor as detailed, and some make it out to be. Sure their are 4 or 5 areas that you can focus your efforts however on my 3 Sprints I found the greatest improvement when I simple added either a rubber ring/band, or a spring from the right side of the steering mechanism to the the other. 70% of your play is found here. RPM ball ends might have contibuted a 2% max improvement. The second greatest area for steering improvement is not in the steering mechanism themselves but in the left to righ (in & out) play found in the front wheel system itsself. Do either the Ball Point Spring mod or simply add a extra o-ring at the interal side of the Dog Bones. that probably helps another 25%.
Another contibutor often overlooked is the tires some folks run. Unless you run high speed BELTED tires your going to have steering & control issues under full throttle due to ballooning tires and a fluctuating minimal contact patch with the surface.
Another contibutor often overlooked is the tires some folks run. Unless you run high speed BELTED tires your going to have steering & control issues under full throttle due to ballooning tires and a fluctuating minimal contact patch with the surface.
Last edited by Critter; 11-06-2014 at 08:46 AM.
#768
No you don't need to buy the rs4 parts as well, the sprint1 part will work alone, although I seemed to recall having to swap out the bearings to fit the shaft and stock sprint 2 steering arms. I can do some better pictures if you still need them.
There are some posts in here that talk about the RS4 3 Steering assembly working with the Sprint 2. And someone confirmed that in a review on this page:
http://www.asiatees.com/display?id=1...&model=RS4%203
But I was wondering if the Nitro RS4 3 steering assembly will also work:
http://www.ebay.com/itm/GPM-HPI-Nitr...-/271629367857
The eBay listing is from someone in the US, so I'd get it faster. Just want to make sure they're the same in terms of fitment.
http://www.asiatees.com/display?id=1...&model=RS4%203
But I was wondering if the Nitro RS4 3 steering assembly will also work:
http://www.ebay.com/itm/GPM-HPI-Nitr...-/271629367857
The eBay listing is from someone in the US, so I'd get it faster. Just want to make sure they're the same in terms of fitment.
That review on asiatees was from me, but I can confirm it works as the pics should show earlier in the thread. The rs4 parts used are the shims, bearings, standoff and ackerman rather than the actual bellcrank arms which are too long but you can use all those bits to make it without the sprint1 parts.
Sorry its a bit vague, if you still need help let me know and I will try get some better pics and explanations up.
Oh and I know people are always asking for a lipo that fits without any modding and I thought I would post these as so far I have really liked them as they have a decent c rating, and good weight in a hardcase as well as 4200mah for £26. Not ROAR approved however
http://www.hobbyking.co.uk/hobbyking...dProduct=19692
Last edited by WaftyCrank; 10-21-2014 at 03:36 PM.
#769
Tech Rookie
Joined: Sep 2012
Posts: 9
I had the same problem with the steering wobble on my Sprint. And I was using your method that I saw on here. But after a while I began noticing that it was starting to become loose again. not as bad but loose. After trial and error I came up with a new mod that has tightened up the right side servo saver and solved the steering wobble. Im gonna post how I did it and what parts are needed for this mod. Maybe somene else has already made a mod like this but I havent seen it in my searches. I hope that it helps all us Sprint owners fix their loose steering.
#770
I had the same problem with the steering wobble on my Sprint. And I was using your method that I saw on here. But after a while I began noticing that it was starting to become loose again. not as bad but loose. After trial and error I came up with a new mod that has tightened up the right side servo saver and solved the steering wobble. Im gonna post how I did it and what parts are needed for this mod. Maybe somene else has already made a mod like this but I havent seen it in my searches. I hope that it helps all us Sprint owners fix their loose steering.
#772
Hi all, apologies if this has been covered before, but do you know of a resource which specifies a FULL build of the Sprint 2?
I recently purchased a wreck, and I have dismantled it to the last screw, cleaned every part, and now am looking forward to rebuilding it... but turning it in to a Flux version by adding a brushless 17.5T motor and upgraded ESC.
I am used to manuals from Tamiya which are brilliant in building their cars, so I'm hoping there is something similar to reference from.
The manual that came with the car is great for maintenance tips etc, but doesn't cover the steps required to build one from scratch.
Any suggestions and advice would be greatly appreciated... and have a fantastic New Year everyone!
Thanks
I recently purchased a wreck, and I have dismantled it to the last screw, cleaned every part, and now am looking forward to rebuilding it... but turning it in to a Flux version by adding a brushless 17.5T motor and upgraded ESC.
I am used to manuals from Tamiya which are brilliant in building their cars, so I'm hoping there is something similar to reference from.
The manual that came with the car is great for maintenance tips etc, but doesn't cover the steps required to build one from scratch.
Any suggestions and advice would be greatly appreciated... and have a fantastic New Year everyone!
Thanks
#773
Hi everyone, I found this thread a couple of days ago and finally finished reading it. I have been a sprint 2 owner for several years now, but recently I've decided to give the car a try on the race track. Awesome job to everyone who contributed to the thread; it has been a big help to me getting my S2 up to par.
I wanted to share a little mod of my own that I figured out to make the battery holder in the S2 larger and simplify it. This mod allows the S2 to fit up to 25mm lipo packs with no issues. This mod does also require the belt lift mod(post #2) if you want to use 25mm batts.
Only one Part required: Tekno TKR40007K (or any velcro strap set close to 10.5in)
Mod is pretty self explanatory from the pics.
1- Remove stock battery clamps.
2- Wrap strap around aluminum post in front of battery holder and pass strap through its loop.
3- Wrap strap around plastic rear post and velcro it together.
I wanted to share a little mod of my own that I figured out to make the battery holder in the S2 larger and simplify it. This mod allows the S2 to fit up to 25mm lipo packs with no issues. This mod does also require the belt lift mod(post #2) if you want to use 25mm batts.
Only one Part required: Tekno TKR40007K (or any velcro strap set close to 10.5in)
Mod is pretty self explanatory from the pics.
1- Remove stock battery clamps.
2- Wrap strap around aluminum post in front of battery holder and pass strap through its loop.
3- Wrap strap around plastic rear post and velcro it together.
#774
Hi all, apologies if this has been covered before, but do you know of a resource which specifies a FULL build of the Sprint 2?
I recently purchased a wreck, and I have dismantled it to the last screw, cleaned every part, and now am looking forward to rebuilding it... but turning it in to a Flux version by adding a brushless 17.5T motor and upgraded ESC.
I am used to manuals from Tamiya which are brilliant in building their cars, so I'm hoping there is something similar to reference from.
The manual that came with the car is great for maintenance tips etc, but doesn't cover the steps required to build one from scratch.
Any suggestions and advice would be greatly appreciated... and have a fantastic New Year everyone!
Thanks
I recently purchased a wreck, and I have dismantled it to the last screw, cleaned every part, and now am looking forward to rebuilding it... but turning it in to a Flux version by adding a brushless 17.5T motor and upgraded ESC.
I am used to manuals from Tamiya which are brilliant in building their cars, so I'm hoping there is something similar to reference from.
The manual that came with the car is great for maintenance tips etc, but doesn't cover the steps required to build one from scratch.
Any suggestions and advice would be greatly appreciated... and have a fantastic New Year everyone!
Thanks

#775
Tech Initiate
Joined: Nov 2014
Posts: 45
Hi everyone, I found this thread a couple of days ago and finally finished reading it. I have been a sprint 2 owner for several years now, but recently I've decided to give the car a try on the race track. Awesome job to everyone who contributed to the thread; it has been a big help to me getting my S2 up to par.
I wanted to share a little mod of my own that I figured out to make the battery holder in the S2 larger and simplify it. This mod allows the S2 to fit up to 25mm lipo packs with no issues. This mod does also require the belt lift mod(post #2) if you want to use 25mm batts.
Only one Part required: Tekno TKR40007K (or any velcro strap set close to 10.5in)
Mod is pretty self explanatory from the pics.
1- Remove stock battery clamps.
2- Wrap strap around aluminum post in front of battery holder and pass strap through its loop.
3- Wrap strap around plastic rear post and velcro it together.
I wanted to share a little mod of my own that I figured out to make the battery holder in the S2 larger and simplify it. This mod allows the S2 to fit up to 25mm lipo packs with no issues. This mod does also require the belt lift mod(post #2) if you want to use 25mm batts.
Only one Part required: Tekno TKR40007K (or any velcro strap set close to 10.5in)
Mod is pretty self explanatory from the pics.
1- Remove stock battery clamps.
2- Wrap strap around aluminum post in front of battery holder and pass strap through its loop.
3- Wrap strap around plastic rear post and velcro it together.
#778
Hi guys, new to this particular thread and never owned a HPI Sprint before so please forgive my ignorance for my question but I'll fill you in first.
I've just picked up a HPI Sprint 2 roller from eBay and want to set it up for speed runs here locally where we race mainly on a really cool bicycle velodrome.
As I'm well aware of what heaps of torque can do to a drive train when you play with different motor kV's and lots of Lipo voltage, plastic gears tend to suffer a bit

There is a guy (Niel Stubbington) in the UK though that provides an awesome service for some great heavy duty spur gears made from 'High grade Acetal' at
http://www.rwracing.co.uk/cars.html
My question is, what spur gears (48Dp) here are compatible with the HPI sprint 2?
Thanks in advance
John
I've just picked up a HPI Sprint 2 roller from eBay and want to set it up for speed runs here locally where we race mainly on a really cool bicycle velodrome.
As I'm well aware of what heaps of torque can do to a drive train when you play with different motor kV's and lots of Lipo voltage, plastic gears tend to suffer a bit


There is a guy (Niel Stubbington) in the UK though that provides an awesome service for some great heavy duty spur gears made from 'High grade Acetal' at
http://www.rwracing.co.uk/cars.html
My question is, what spur gears (48Dp) here are compatible with the HPI sprint 2?

Thanks in advance

John



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