Clearance between tire and seat tube
08-28-20, 04:26 PM
#1
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Clearance between tire and seat tube
I've put 28s on an old road bike. There is about 2 mm between the tire and seat tube. Is this enough space? What is the worst realistic outcome?
Also, I have wheels with 14 mm internal width and 19.5 external. My undestanding is that 25C would be better for speed but 28s would be better for comfort. Does that sound right?
Many thanks for your help.
Also, I have wheels with 14 mm internal width and 19.5 external. My undestanding is that 25C would be better for speed but 28s would be better for comfort. Does that sound right?
Many thanks for your help.
08-28-20, 04:52 PM
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It's pretty much your call on that. I'd want more space. If something got between the seat tube and the tire, you rear wheel might suddenly stop.
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08-28-20, 04:53 PM
#3
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I've put 28s on an old road bike. There is about 2 mm between the tire and seat tube. Is this enough space? What is the worst realistic outcome?
Also, I have wheels with 14 mm internal width and 19.5 external. My undestanding is that 25C would be better for speed but 28s would be better for comfort. Does that sound right?
Many thanks for your help.
Also, I have wheels with 14 mm internal width and 19.5 external. My undestanding is that 25C would be better for speed but 28s would be better for comfort. Does that sound right?
Many thanks for your help.
I put 700x41 tires on my bike that was spec'd for 700x40 max. A couple mm clearance in the bike shop. I drove the bike to New Mexico and rode pavement in early June. The tire started rubbing against the carbon chain stays. Heat expansion. Not good.
Last edited by DeadGrandpa; 08-28-20 at 04:58 PM.
08-28-20, 04:54 PM
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If you're riding on clean, dry pavement, I wouldn't give it a second thought. If it's muddy or sandy, you might have an issue.
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08-28-20, 05:00 PM
#5
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Frame building options: longer chain-stays , or an S bent Seat Tube... so seat tube bends around the tire.
Dimpling the seat tube is another technique done to keep the chain stays short ...
Only in so far as the PSI of the Slightly Wider tire's operating PSI is an RCH lower..
( vernacular for a rather tiny amount ) 3mm in this case..
..
Dimpling the seat tube is another technique done to keep the chain stays short ...
My understanding is that 25 mm would be better for speed but 28 mm would be better for comfort. Does that sound right?
( vernacular for a rather tiny amount ) 3mm in this case..
..
Last edited by fietsbob; 08-28-20 at 05:07 PM.
08-28-20, 05:02 PM
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The OP wants to know if he can fit a slightly bigger tire in his existing frame, and your response is to rebuild the frame?
08-28-20, 07:04 PM
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If the tire clearance under the rear brake caliper (assuming there is one) is equal to or less then that behind the seat tube then the caliper will be a "wiper" to clear the tire of road derbies.
I suppose the answer depends on the value of the paint job
Andy
I suppose the answer depends on the value of the paint job
Andy
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AndrewRStewart
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08-28-20, 08:31 PM
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Depending on the geometry of the bike the wheel might not go on with the tire inflated. There might be too little a space between the seatstay and tire to get the wheel far enough forward to slip into the drop-outs. You will have to inflate the tire after the wheel is on.
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08-28-20, 10:34 PM
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I've put 28s on an old road bike. There is about 2 mm between the tire and seat tube. Is this enough space? What is the worst realistic outcome?
Also, I have wheels with 14 mm internal width and 19.5 external. My undestanding is that 25C would be better for speed but 28s would be better for comfort. Does that sound right?
Many thanks for your help.
Also, I have wheels with 14 mm internal width and 19.5 external. My undestanding is that 25C would be better for speed but 28s would be better for comfort. Does that sound right?
Many thanks for your help.
