sherbornpeddler

Using my Al Krietler rollers this winter, I just put a new Michelin Krylion Carbon tire on my rear wheel and am now getting what appears to be black lumps on the free roller. It appears to be rubber tire debris and most scrapes off leaving only a stain until it builds up again after 20 miles.

This is new so I wonder if the tire is unusually soft and tearing away? It really is noticeable and only on the rear "free" roller. I use 115 psi, as I did with a Conti Grand Prix (got about 4000 miles before threads appeared).

Anyone?

SpongeDad

I like Conti GP Four Seasons for inside work. They're decent enough tires to ride outside, tough for crappy winter debris, but really don't leave any residue on rollers or trainers (I have both).

sherbornpeddler

SDad, so you've seen this residue phenomenon?

sherbornpeddler

Is this limited to brand new tires then they wear in" or is this tire doomed? Is it defective or fine for outdoor road use and switch to a different brand for roller work?

Carbonfiberboy 

Never seen this problem, never used those tires.

CMOS

Continental makes a tire that is specifically made for trainers. They run cooler and they are pretty much bullet proof.

krazyderek

I've seen this problem before. When i swtiched to Alu rollers my tires where way louder so i had to start searching for new slicks that would be quiet. I got some krylions, and pro race 2's but both had the gummy problem on the rollers, it went away after a few rides out on the roads to work the tires in a bit, but they were still loud as hell on the Alu drums.

Best tire i've ran across thus far was one that someone on these boards recommended was a Vittorria Rubino Pro SLICK, whisper quiet out of the box and no gummy problems, and they only get quieter as you ride them on a road a bit and wear them down a tiny bit.

crash and burn

I have the Michelline Pro2 Race tires on my bike and I also noticed the rubber comming of when using the trainer. Its actually leaving a flat spot on the tire. I was planning on buying new tires right before daylight savings hits and I can go back outside to ride.

auk

The Pro 2's are the worst tire you could use on a trainer. Very sticky tire, and great for road riding, but the heat buildup on the trainer kills them very quick. Buy a Conti Trainer tire. Amazing the difference it makes.

sherbornpeddler

Anyone guess why the residue appears on one roller, the free roller and not the inner roller? Is it really heat and maybe the curvature of the roller? I guess this makes sense but I imagine some roads get pretty hot. I was guessing this was some initial wear limited to new tire "bead"?

I didn't notice this at al when I used a conti which I understand had silicon in the formula; maybe more heat resistant? I bet a tire dude knows.

Giro

1. Agree with CMOS & Auk; Continental Ultra Sport Hometrainer tire should fix this LINK. Several posters including me will also vouch for it being a most difficult tire to mount. Good excuse to buy a Kool Stop Tire Bead Jack LINK.

2. The front tire's load is distributed on only one roller, resulting in more deformation and increased wear/heating. Typical front/rear weight distribution is about 45% front, 55% rear. The rear tire is supported by two rollers so each roller deforms the tire the equivalent of about 30% of the weight (rear wheel is slightly down between the rear rollers, so it is a bit "wedged" between them & thus force may be closer to 30% rather than 55% / 2 = 27.5%). Front tire on one roller gets deformed by a full 45% or about 1.5X as much as the rear. Most of the energy loss on rollers (assuming no fan or other resistance device) is due to tire deformation LINK. Those watts you generate end up as heat. Since the front tire is deformed more, it is probably heated more.

You also might check front vs rear tire pressures. Is the front tire essentially exactly on top or slightly back? The further back from exactly on top of the roller the more the front tire is also "wedged" against the roller for still higher forces and still more heat.

krazyderek

He's getting wear on the rear most roller, the one not linked to the front roller.

I have conti sport ultra's and you're right, they don't heat up as much cause of a different formula for the "rubber" in the tire, but they're kinda eary loud. I haven't tried the yellow conti trainner tire because you can't use it outside, and i like to use my powertap wheel both on the trainner and on the roads.

Hence i've been happy with the vittoria tires for some time now.

Giro

[QUOTE=krazyderek;6046778]He's getting wear on the rear most roller, the one not linked to the front roller.[QUOTE]

Damn, another theory ruined by experimental evidence.

Well, maybe the tire heats up on the middle roller and is still warm & sticky when it gets to the rear roller. The front tire gets more time to cool off. I assume the rear roller is not driving the Kreitler accessory flywheel or fan unit.

___________________
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sherbornpeddler

My Dear Theorists,

Yes, my front wheel is slightly aft of top dead center.
No accessories attached to any roller.

With Sherlock Holmes-like magnifier, I do see debris "downstream" of the first of the two rear rollers; that is downstream of the drive roller. I'll try another run manana and observe again. The front wheel, btw, is a different tire and also never shown any residue downstream.

Giro

In the interests of bicycle science, you need to mount another new Michelin Krylion Carbon tire but on the front wheel for a control. To be really scienterrific, weigh the tires before and after (or entire wheel on a really good balance).
_____________________
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sherbornpeddler

Hmmm.....My front tire is currently in good shape so this would be an investment. I guess it is the cost of money for the life of the front tire.
Science you say?

sherbornpeddler

I've put 300+ road miles on the tire then back on the rollers and no more rubber residue. I think geometry of the new tire amplified shear forces on the tire so it rips the tire rubber off. I don't think (aka speculate) this is ripping, not heat related melting.
Anyway, after riding 3-400 miles, no more residue.

kster

FYI, I'm also using Michelin Krylion Carbon tires with aluminum Krietler rollers and I haven't seen any rubber residue on the drums (but my tires are well worn from street use).