mechanical-advice

Q & A - Bicycle Tyres

 

Tight Tyres

!

I have Campagnolo rims on my racer which seem to be a slightly larger diameter (68cm approx) than most 700c rims which is causing havoc for me when doing tyre changes. Do you know of a tyre that is slightly larger than the norm that would fit these rims better enabling easier tyre removal?

No, I don't know if "easier to fit" tyres. But I'd say that steel bead can be considerably easier than kevlar bead, especially when new. Mostly I'd urge you to check your rim tapes. Some are good (Velox cloth tape), some are crummy (any sort of rubber tape for example). A common mistake is to add a good tape over a crummy one, making tyre fitting quite difficult. It's not so much the outher diameter of the rim which determines how easy or difficult a tyre is to fit, as the amount of movement the tyre is allowed within the rim. A thick rim tape makes a tyre harder to fit, 2 rim tapes can make it almost impossible. At a pinch, you could use the Ritchey rim tape which is thinner than the Velox, but I don't think as reliable; it's a solution we've not had to resort to yet. Also, when removing a tyre or in the final stage of fitting, squeeze ALL the aire you can out of the tyre and close the valve so it doesn't fill again. Wrap your chest and arms around the tyre and have it pushing on the floor. A little bit of air makes a big difference. Good luck!

Tyre Width

!

Hi Guys,

 I commute 20km each way to work on a Trek MTB 4800. Good strong bike, served me well for 7 years. 

I currently use 1.5 tyres and am interested how skinny I can go? I saw your slickasaurus 1.1’s which look interesting.  

What issues should I consider before going really skinny, and how much benefit will I get? 

Scott

Hi Scott,
    Pressure is more important than width for lowering rolling resistance. That and tread pattern (of lack of it) and tyre construction (weight and casing flexibility). The 1.1 tyres might give a slightly lower rolling resistance than say a 1.5, and also give slightly better acceleration through lighter weight. But you don't want to put them on wide rims, which would expose the sidewalls to damage from whatever you happen to run over. A too-narrow tyre on a wide rim will mean the delicate tyre sidewalls are not hidden away behind the tough tread section.
    A narrower tyre will also lower your gearing marginally.
Cheers,
Mark.