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Minimum clearance?

Old 08-18-19, 02:43 PM
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dombey19
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Minimum clearance?

After a decade of cheaper wheels on my Litespeed, I decided to do what I intended to do years ago, replace the wheels. I originally was running 700x23 and several years ago (when everyone was touting fatter tires) I mounted 700x25 and had no problems. The wheels I bought, HedArdennes, use a 25 mm. rim, and they allow the tires to expand more than they did in my old Fulcrum wheels. Everything clears the fork and rear stays, but barely. I don't know how to estimate mm., but I would say I have about 1/8 inch of clearance at all critical points. Should I just not worry about this, reasoning that if the tires clear they clear, or should I back away from these wider rims and find something else?
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Old 08-18-19, 03:00 PM
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masi61
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2If it clears,you’re golden.

I have a nylon metric dial caliper that I bought for under 20$ years ago (General branded) and I use it all the time. It helps you quantify what you suspect. For example, the 25mm tires you are running on your HED Ardennes rims - they could stay true to the 25 spec due to the generous interior volume they afford, or they might bump it up close to 27mm. It might be nice to know.

So long as your brake bridge, the underside of your fork or the top of your brake arches aren’t getting ground down, I would say to just enjoy the wide tire goodness. And don’t hesitate to lower your tire pressure accordingly.

I’m running Challenge Criterium 25mm open tubulars on my Velocity A23 rims and find them to be positively plush in the ride department. OMG: today I did a leisurely but brisk 40 miler with just 72 psi front and 82 psi rear. And I weigh #190 and the roads are rough around here.

If if you really want to maximize the lovely ride that your fat 25’s are going you, may I suggest also installing latex tubes? Again - the feel you get from these, combined with the lower pressures is plush. I’m loving it. Any harshness you used to experience from your frame and fork gets dialed right out with a set-up like that. And in my experience the latex tubes, once successfully installed do not flat any more often than butyl inner tubes.

Last edited by masi61; 08-18-19 at 03:04 PM.
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Old 08-18-19, 03:33 PM
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WhyFi
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Originally Posted by dombey19 View Post
After a decade of cheaper wheels on my Litespeed, I decided to do what I intended to do years ago, replace the wheels. I originally was running 700x23 and several years ago (when everyone was touting fatter tires) I mounted 700x25 and had no problems. The wheels I bought, HedArdennes, use a 25 mm. rim, and they allow the tires to expand more than they did in my old Fulcrum wheels. Everything clears the fork and rear stays, but barely. I don't know how to estimate mm., but I would say I have about 1/8 inch of clearance at all critical points. Should I just not worry about this, reasoning that if the tires clear they clear, or should I back away from these wider rims and find something else?
For the purpose of published tire clearance, a min of 4mm worth of space on all sides is the standard. 1/8" is 3mm and change. I'd say you're good, but keep an eye on them - I've never confirmed myself, but many say that tires will expand over time.
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