Speed Runners ~ How Fast Did You Go Today?

[Darren W]

Still shaking from a blow over at 100ish which incredibly did no damage other than body scuffs. My own fault as I put too much power in and made the rear squat. After a check over I ran again with a much more gentle input.

 

[jondilly1974]

Still shaking from a blow over at 100ish which did not damage other than body scuffs. My own fault as I put too much power in and made the rear squat. After a check over I ran again with a much more gentle input.

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Preload the rear shocks as tight as you can. You really don’t even need rear suspension travel. Guys like Raz simply remove their springs and use rubber spacers on the shock shaft to have as little give as possible.

 

[Darren W]

Preload the rear shocks as tight as you can. You really don’t even need rear suspension travel. Guys like Raz simply remove their springs and use rubber spacers on the shock shaft to have as little give as possible.

The silicone damper wedge was my next addition. Now moving faster on that mod as I don’t think I will be as lucky on the next blow over. I’ll sort out some video later if it’s in shot.

 

[Darren W]

As promised a video of the flip caused by a little too much finger compounded by a very loose rear end.

 

[LibertyMKiii]

As promised a video of the flip caused by a little too much finger compounded by a very loose rear end.

Glad it was not damaged and that you were safe!
This is a good time to remind others to stand in a safe spot. I personally park my SUV on the side of the road and stand on top. From the many blow overs I have seen the car rarely goes over 3ft off the ground.
I like having functional legs to walk on... also a perk of standing on top of your vehicle is much better view when the car is 1200+ feet away.

 

[Darren W]

Glad it was not damaged and that you were safe!
This is a good time to remind others to stand in a safe spot. I personally park my SUV on the side of the road and stand on top. From the many blow overs I have seen the car rarely goes over 3ft off the ground.
I like having functional legs to walk on... also a perk of standing on top of your vehicle is much better view when the car is 1200+ feet away.

No damage other than body, wheels and a battery scuff.
I agree on using this as a reminder for safety, having spent all of my life in motorsport and many years racing 1/5th cars I know where a good standing spot is! As you can see, I stand by the tyres so I can hit the deck if need be and I almost did drop as it slid towards me.

 

[BashingBrian]

As promised a video of the flip caused by a little too much finger compounded by a very loose rear end.

@Darren W .. Where is that..?? If it's top secret pm me..?

 

[Notoriousone]

Took out the Limitless GT again with a slight gearing change, it did 127 mph on GRP S5's. I could have (and should have) held it open for maybe half a second longer before rolling off throttle, but since the last blowout I had I've become a bit cautious with GRP's and haven't gone all out using them since.. The two rear stabilizers I bolted to the original Limitless wings seemed to help, it was planted and stable the whole run.
The car went straight as an arrow and definitely has more speed in it, once I make the switch to BSR foams (and other brands) with their larger tire rollout I should see at least 7 or 8 mph more I think.. The idea of switching to foams makes me nervous though, because of many reasons that have been talked about regarding low traction.. Hopefully it will go well, I might try it with a different car next weekend

 

[Darren W]

@Darren W .. Where is that..?? If it's top secret pm me..?

It’s not top secret!! It’s Bedford Autodrome, one of the 5 circuits the group I work for owns.

 

[BashingBrian]

I could really do with going there..? the roads round my way are just no good for speed runs..?

 

[LibertyMKiii]

Took out the Limitless GT again with a slight gearing change, it did 127 mph on GRP S5's. I could have (and should have) held it open for maybe half a second longer before rolling off throttle, but since the last blowout I had I've become a bit cautious with GRP's and haven't gone all out using them since.. The two rear stabilizers I bolted to the original Limitless wings seemed to help, it was planted and stable the whole run.
The car went straight as an arrow and definitely has more speed in it, once I make the switch to BSR foams (and other brands) with their larger tire rollout I should see at least 7 or 8 mph more I think.. The idea of switching to foams makes me nervous though, because of many reasons that have been talked about regarding low traction.. Hopefully it will go well, I might try it with a different car next weekend

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Nice work Darin! I bet that car is tuff to see?

 

[Mr.Duke]

Get the GSM-020 as long as you have a smart phone.

Should be here in time to run Sunday morning if it stays dry overnight

 

[Notoriousone]

It’s not top secret!

Nice work Darin! I bet that car is tuff to see?

Surprisingly no, it wasn’t that hard to see, the road I was on had a grey asphalt color and was sunny with no shadows, so I could see the car even from about 1100 ft away. What makes a huge difference in how far away you can see something is how uniform in color the surface its on is. This road was all the same color so the car was visible from far away though it basically looked like a moving black dot lol

 

[Darren W]

Found the limit for this brand new set of Hoons on the second pass. Luckily I heard it starting to split so no damage. Time to move to foams.

 

[LibertyMKiii]

Found the limit for this brand new set of Hoons on the second pass. Luckily I heard it starting to split so no damage. Time to move to foams.

Congrats on the 125 Run. Tires are SUCH a frustration in this hobby!
Rubber tires are 50% risk at these speeds... Even with GRPs and re-glueing the sidewall to rim bead.

Is this a belt inside the rubber of the tire (see red arrows added)? The rubber is significantly thicker than I realized. I wonder if shaving them down would reduce enough mass to help mitigate the separation? How many mm is that? Appears like 3-4? If those are chords 1/2 way through the rubber then shaving them down wont work.

Same thing is a factor on foams, but that shifts up to the 150+ range where it comes unglued. Shaving foam down is much easier than this rubber....

 

[jondilly1974]

Congrats on the 125 Run. Tires are SUCH a frustration in this hobby!
Rubber tires are 50% risk at these speeds... Even with GRPs and re-glueing the sidewall to rim bead.

Is this a belt inside the rubber of the tire (see red arrows added)? The rubber is significantly thicker than I realized. I wonder if shaving them down would reduce enough mass to help mitigate the separation? How many mm is that? Appears like 3-4? If those are chords 1/2 way through the rubber then shaving them down wont work.

Same thing is a factor on foams, but that shifts up to the 150+ range where it comes unglued. Shaving foam down is much easier than this rubber....

View attachment 100443

Well at least we know it’s easy to wear out a set of Hoons. Just toss in gearing for about 90mph and run a pack. Instant removal of those few mm of rubber ?✌?

 

[Darren W]

Congrats on the 125 Run. Tires are SUCH a frustration in this hobby!
Rubber tires are 50% risk at these speeds... Even with GRPs and re-glueing the sidewall to rim bead.

Is this a belt inside the rubber of the tire (see red arrows added)? The rubber is significantly thicker than I realized. I wonder if shaving them down would reduce enough mass to help mitigate the separation? How many mm is that? Appears like 3-4? If those are chords 1/2 way through the rubber then shaving them down wont work.

Same thing is a factor on foams, but that shifts up to the 150+ range where it comes unglued. Shaving foam down is much easier than this rubber....

View attachment 100443

The rubber is 3.5mm thick and does have a cord in there. This has failed due to a manufacturing fault. The mesh is folded as you can see in the photos. I’ve pulled the rubber back and you can clearly see where it goes back to the correct orientation.
Good to know it’s not a car setup or acceleration finger issue.

 

[LibertyMKiii]

The rubber is 3.5mm thick and does have a chord in there. This has failed due to a manufacturing fault. The mesh is folded as you can see in the photos. I’ve pulled the rubber back and you can clearly see where it goes back to the correct orientation.
Good to know it’s not a car setup or acceleration finger issue.

Thanks for confirming!
I still am a believer in rubber tires. I want to come up with a solution that makes them more reliable.
The silver Hoons (only available in 5 spoke rim) are reported as far more reliable at high speed. I may explore adding BSI glue to the inner belting as well as cutting some grooves in the tire to add external belting.

It sure would be nice to have a 160+mph, safe, high grip rubber tire.

 

[Darren W]

Thanks for confirming!
I still am a believer in rubber tires. I want to come up with a solution that makes them more reliable.
The silver Hoons (only available in 5 spoke rim) are reported as far more reliable at high speed. I may explore adding BSI glue to the inner belting as well as cutting some grooves in the tire to add external belting.

It sure would be nice to have a 160+mph, safe, high grip rubber tire.

Years ago when i ran speed runs with EDF cars i used to make my own PU tyres moulded on to Schumacher plastic disc wheels. they never chunked and had a lot of grip. They were good for 130mph back then so with the advancement in chemical technology a similarly constructed tyre could go much farther, maybe..

The first company to release a tyre and wheel assembly that can reliably top 200mph will clean up the speed run market. It's just a shame that no company wants to take on all of the R&D for such a small proportion of return.

 

[LibertyMKiii]

Years ago when i ran speed runs with EDF cars i used to make my own PU tyres moulded on to Schumacher plastic disc wheels. they never chunked and had a lot of grip. They were good for 130mph back then so with the advancement in chemical technology a similarly constructed tyre could go much farther, maybe..

The first company to release a tyre and wheel assembly that can reliably top 200mph will clean up the speed run market. It's just a shame that no company wants to take on all of the R&D for such a small proportion of return.

The foam shaved down to small diameter will be the absolute best solution to combat centrifugal forces pulling it off the plastic wheel. I cant imagine any other tire material with such a low mass. I had bad experiences with foams and wont run them on a 1/8 or 1/7 car again.... unless I had access to a large airstrip ?

My thought of the ideal rubber tire for speed would be having the tire glued direct to the wheel and bypass the sidewall and foam insert method.

I am preparing to test my 4tec 2.0 again on foams, after fixing some suspension issues. Very nervous about it....