BST extra wide rear

Commuta_Busa

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Ok, here's my question to anyone who has first hand experience. I was looking at the 6 5/8" wide BST rear wheel and wonder if anyone has noticed a noticable/measurable improvement in their launch (60 ft.) from running the extra wide rim.

I understand the benefits of running a wider rim (flattens out the tire) which gives you a better contact patch. I just don't know, in my mind, if I can justify the costs unless their really is an improvement.

Also let me know what you're running as far as NA / Juice / Turbo. Maybe this extra wide rim benefits the nitrous guys who launch on the spray compared to the turbo guys. The amount of torque on the launch may be more or less and if it's only the guys really "throwing it down" on the line that benefit from this then it may not justify me looking into this sized rim.
 
Find someone with a newer Dynojet 250i with a climate controlled dyno room so results remain apples to apples throughout the testing day. Thats what we have here at HPC. You will want to do negative horsepower testing. This is critical for the guy searching for every inch of extra power.

The operator will explain the complete process to you, it is used to show drive train drag and can help with performance testing with engine lubricants, chains, lightened cranks, chain lube, o-ring vs. non-oring chains, aluminum vs. steel sprockets, wheels and rotors or on anything rotating.

Very simple process if done correctly. If a modification is resulting in less drag on the drive train it should result in faster acceleration. Something as simple as spreading the rear brake pads reduces drag freeing up HP.
 
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I'm not a fan of dynojet dyno's and tend to steer clear of them, sorry. My focus isn't in the reduced drive train losses but the actual grip (launch) benefit. Thanks for the dynojet info. Alot of people would be surprised to know that a chassis dyno can do a little more than just calculate torque.

Maybe my questions is a little confusing. I'm simpy trying to find out if anyone has been able to increase their rear wheel thrust at launch significantly or not. a wheel dyno isn't going to be able to answer this.
 
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I'm not a fan of dynojet dyno's and tend to steer clear of them, sorry. My focus isn't in the reduced drive train losses but the actual grip (launch) benefit. Thanks for the dynojet info. Alot of people would be surprised to know that a chassis dyno can do a little more than just calculate torque.

Maybe my questions is a little confusing. I'm simpy trying to find out if anyone has been able to increase their rear wheel thrust at launch significantly or not. a wheel dyno isn't going to be able to answer this.
Contact patch is also drag. I do understand your question better now.

Get in touch with Wild Bill Warner....he has a pretty fast naked turbo busa 240+ he has been with a 240 Perelli Tire and a Carrozzeria 240 rear wheel. Pretty smart guy who does his own work, he should be able to answer your questions more accurately since nobody launches like they do at the drag strip on a non-treated surface like a LSR event. His input should be more applicable to your needs.
 
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yea, I've chatted with Billy plenty of times. We talked a while ago about his 240. The 240 is just way overkill for my app. I'm still running a normal sized 190 :laugh:
 
yea, I've chatted with Billy plenty of times. We talked a while ago about his 240. The 240 is just way overkill for my app. I'm still running a normal sized 190 :laugh:
I guess you answered your question then, he seemed to like it a lot. Contact patch was one of the things we chatted about as well.
 
No, my original question still stands. The 6 5/8" rim isn't meant for the 240 tire. It's for my 190.

I'm wondering what results have been made using the 65/8" w/190 tire.
 
Im running a 330....that has plenty of contact patch. Fist day out I was running 28psi in that big tire...then raised the psi to 38. Yes thats a lot of air ( ride 41psi on the street) but got more of that big thing off the ground and I picked up like 6-8 more mph on the topend. It could have been other things that made the diff, but I think it was the tire PSI.
 
A 6-5/8 rim will definitly flatten out your contact patch, and should improve your footprint if your using a tire like a Shinko ultra soft or a Mickey. These are tires with an already flattened surface that benefit from a wider rim. I have tried running higher profile tires (the Pirrelli Super Corsa) for LSR on a 6.75? rim before and had a harder time getting the bead to seat. For a while there they were marketing those tires for drag racing as well, but I never thought it had any contact patch even after they were mounted on a wider tire.
 
Yea the beading is very important and in the past was a serious problem. The BST extrawide rim has an added antislip treatment which they've been succesful at keeping the tire bead from moving.

A 6-5/8 rim will definitly flatten out your contact patch, and should improve your footprint if your using a tire like a Shinko ultra soft or a Mickey. These are tires with an already flattened surface that benefit from a wider rim. I have tried running higher profile tires (the Pirrelli Super Corsa) for LSR on a 6.75? rim before and had a harder time getting the bead to seat. For a while there they were marketing those tires for drag racing as well, but I never thought it had any contact patch even after they were mounted on a wider tire.
 
The wider rim shows it's greatest benefit in higher hp situations such as PST (Pro Streetbike) and when track conditions are sub-optimal. If your running a stock or non-strocker big bore the difference will be marginal and you will lose a few MPH in trap speed.

Hope this helps.
 
thanks for the info. I'm not at super turbo levels but I do run a stroker/big bore :thumbsup:.
The wider rim shows it's greatest benefit in higher hp situations such as PST (Pro Streetbike) and when track conditions are sub-optimal. If your running a stock or non-strocker big bore the difference will be marginal and you will lose a few MPH in trap speed.

Hope this helps.
 
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