Bonneville America Forums Forums Technical Forums Performance Mods Dyno Tire Wear?

Here's a question I don't have any feel for or answer to. One of the tire manufacturer's (Bridgestone/Firestone) has listed on their website as recommending against running a tire on the street after using it on a Dyno test.

Pasted from the Bridgestone/Firestone Motorcycle Tire Safety & Maintenance Manual
re: Dyno Testing

"Do not use a tire on the road that has been subjected to motorcycle dynamometer testing. The stress from this process may result in tread compound degradation and possible tire failure."


Thoughts? - Input? Given their recent public legal battles, I'm sure in-house legal staff has ample input into anything the company puts out, then again there might be a safety issue to consider? I don't know.

i guess my opinion is i won't buy Bridgestone/Firestone tires.

that's very interesting. i haven't heard of that.

cat

I've seen this before somewhere. I recall that what I originally read said "any tire". I can't figure what extra stress there would be, but, there seems to be something to it.

I've never heard that but in a way I see how the stress can cause the tire to be goofy. I dyno'd my last tire at least 5 times though and still rode 90mph to Georgia and back without a hitch. I'll try to be more observent in the future though.

I don't pretend to be a tyre guru; more of a tired guru, from the land of long nights & short days. At least until it warms up a bit. Then my energy level goes exponential.

I saw this and figured it might be food for thought (or disagrement) for all the tweakers, adjusters, rejetters, air box eliminators, cylinder borers and exhaust system openers.

Then again, if true, it might save somebody's neck out there if they remember to give the sidewalls an extra close "squint".

ride safe!

jh

Well, I couldn't stand it so I called Bridgestone/Firestone and talked to Norris "T.J." Tennent (1-800-543-7522 Ext. 3591), who is the Product Manager for the Motorcycle/Kart/Fuzion tire division.

He told me that because the drums in dynos are geared way low, they build up a tremendous amount of heat in the center of the tread which can lead to failure.

He also said that when they get tires back that have failed, their engineers can spot a dyno caused failure immediately.

Finally he said the best thing to do is go to a shop and ask for a scrap tire and do the dyno with that, or wait until you are about to replace your tire and do the run then.

Very interesting....

Phil,

I will be forced to recommend you for either a promotion or a raise in pay. In the interim, I'll buy a brew (after the ridin's done) next time your in the neighborhood.

Nice follow-up!

john

That's in the service manual as well. I suspect the problem might be that, if the bike is not perfectly aligned with the rollers, the tread could wear at a bias that could make handling freaky. The manual specifically says "rolling road" dynos, which could mean a treadmill type.

Given my experience with Bridgestone/Firestone tires, I would imagine their next public enlightenment will be to advise against driving thru curves with their tires.
Anytime you can put out a pre-emptive statement that covers your butt, any related future failure can be resolved with a "We told you so..." The public will view this as a benevolent warning, when in reality, an honest statement like "We make crap tires" would be more accurate.
That's how I see it, as always, your results may vary...

I wonder how many tires have failed with all the dyno drags going on at bike events. Sounds like a class action law suit in the making. I bet the legal eagles are already licking they're chops..

I hear ya' Trash. Why don't we have motorcycle tires littering the roadways like the crap off some semi's.

I am getting ready to replace my tires so I might as well get the dyno done before then and that don't mean I agree with that guy. Just doesn't sound plausible on a grander scale.

The Bridgestones are tractor tires IMO, any good dyno shop will align the bike properly, if Bridge/Fire has a concern it is probably due to their own products. The stock tires are general use tires, much better tires out there, like the Metzlers on the SMs. I switched at 4K to Avon Venoms and what a difference in tracking, bikes geometry, overall ride and feel. Cornering is very sweet. The Bridges are very hard tires, but my contension is the dyno shop moreso than the tires themselves, although the Bridges are bottom of the ladder when it comes to tires on the TA. If it was such an issue I would suspect dyno shops would have a big-****** sign posted in this regard. Never heard this one before but suspect others havent either. How paranoid are you?? If mucho, change to a better tire and not worry bout it.

OK, i have kicked theis about for a bit and here are my thoughts. Could be true, part true, pure WAG, but I can see a few points that would make a tire maker nervous, especially one with as poor a track record as the stones.
1. any misalignment could cause a biased wear pattern that would buggar handling for the next few hundred miles.

2. Running up to full power in top gear without any air induced drag to slow the bike could easily excede the max speed rating of the tire and start it breaking apart.

3. Running the rear wheel to max power (therefore max load and speed) with the bike standing still could result in exessive tire heat that may start the tire breaking apart. While they usually have some sort of fan or blower keeping the engine cool, it doesn't necessarily cool the tire as much as real air flow might.

Now, unless you are on the salt flats, you would usually be varying the power quite a bit to avoid crashing if you were actually riding. On a dyno, on the other hand, it's just power up to max, hold it whilst taking some readings and maybe tweeking a few adjustments, and then shut down, so I can see the overheating thing being a real factor.

Bugger the dyno I'm on my forth back tyre now after 19000,tuned the bike myself with the help of Pat,if I had a Rocket111 I'd be blowing tyres at 2000 if I was lucky,and yes I ride hard