jberenyi

I have a set of Fulcrum Racing Zero wheels mounted on a custom Lynskey frame. I have always used 23c tires but I wanted to install new 25c tires. The front is fine but on the rear the tire is slightly rubbing my frame on the non-drive side only due to the bi-ovalized tubing setup on that side only. At this point I can think of only two options; go back to 23c tires or dish the wheel over more to the cassette side. My concern with the latter is alignment and what it will do to the handling both low and high speed especially when going down hill. Anyhow, I'm asking the experts what I should do in this situation.

Kimmo

Looks like you're stuck with 23s; adding even more dish is a bad idea. If you had to go the other way, removing a mm or so wouldn't be the end of the world, albeit a bit nasty in principle.

But first, maybe make sure your wheel has enough dish in the first place - is it the same if you flip your wheel?

Or perhaps you could consider having a slight dimple put in the stay...

jberenyi

I have a feeling I'll be stuck with 23's too. Can't do the dimple option because the frame is painted and it would crack the paint. I paid $1200 for the paint job back in the day when Lynskey offered that service. Plus it would be very difficult to dimple titanium. BTW, just checked my front wheel and its touching the Campy brake calipers as it turns. This is not good. Looks like 23c is the only way to go.

Dean V

I bet you were always happy to run 23's in the past!
Nothing has changed apart from 25mm+ tyres now being the fashion.

HTupolev

Don't play games with fractions of a millimeter. ALWAYS have healthy clearance.

If 23s worked fine for your before, keep using 23s.

If your 23s ride harsh, check your tire setup. Make sure you're not pumping your tires unreasonable stiff per your weight and the riding you're doing. If you're using low-end or low-performance tires, get high-end racing tires. If you're using butyl inner tubes, consider trying out latex.

If you have a significant need to go significantly wider than 23s, don't play games with fractions of a millimeter; get a new frameset with wider clearances.

GrainBrain

What tires? And how much clearance do you have with your 23s? I'd grab a caliper and measure the tire width, could be your specific brand of 25s are bigger then advertised?

bruce19

I have a similar "problem" with my Guru Sidero (steel). Tolerances for the rear tire are small. I have been running 25s (Vittoria) and I check the clearances before every ride. I was running 23s and switched to 25s. Either because I'm insensitive or the differences are over-rated I have felt no significant difference.

Iride01 

Not all tires ride the same. So try different brands and models in the size you can put on the bike. The Vittoria Rubino Pro III's ride very much better than the Continental Ultra Sports I previously rode. I did go from 23 to 25mm when I changed, but I think the thread count and the tread compound make the difference that I am seeing. I'm riding the 25mm Vittoria's at 20 to 25 pounds more PSI than I did the Continentals and I still think the ride is noticeably more comfortable on the new ones.

I'm sure that some of Vittoria's tire models ride crappy, and just as certain that some models of Continentals or other brands ride as well as these. You just have to change up what you buy till you find something you are happy with.

As for what you can do about what your got..... Can the spacers on the axle be changed to shift the entire wheel over? It will require some DR adjustment if you can and it might put the chainline off far enough to cause some other issues. I also think that you need more than a few mm of clearance though to safely handle road trash you might suck up, but you should be able to gauge what you are comfortable with.

raria

Perhaps the problem is the Fulcrum Racing Zero wheelsets? Fulcrum don't even recommend mounting 23s on that wheelset only 25-32mm.

Perhaps a narrower wheelset will make the tire "taller" rather than "wider" and hence prevent rubbing on the stays?

jberenyi

Your Fulcrum recommendation for size above may be year specific. I bought these Fulcrum rims before the 25mm popularity. Not sure what year they are. My rims inside measure 15.5mm and outside 21mm. Should be fine to run 23mm tires.

DannoXYZ 

If you have 2mm on right between tyre and stay, then yes, you can move wheel over. Don't even have to change dish. Most of the time, there's a TONNE of space between smallest-cog and dropout. So I just move a 1mm washer from right side of axle to left and that's it!

I usually do this anyway and re-dish wheel to reduce dish amount. I aim for 4mm gap between smallest-cog and inner dropout face. Sometimes I can reduce dish by 2-3mm this way.