# How big a tire Question



## Sven (Feb 19, 2020)

What is the biggest 700c tire that can be fitted into a schwinn unmodified 10 speed frame?  Also with the derailleur installed. 

I know it is not a 700 x 40c . There is no margin for error between the tire and frame. A 38 would give it another millimeter on each side.


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## Duchess (Feb 25, 2020)

Beware of trying to get too tight unless you know the tire as, not only will the clearance vary due to rim width, but the stated number might not be exact. I know on some more performance tires, manufacturers will call something, say a 28mm width, when it's really a 26 or 27 so they can advertise it as being lighter than competitors' "28"s. I don't think it's like putting hogs into renal failure to fatten them up for auction where an unscrupulous few end up pushing everyone else to follow or be left behind (or so I hear, I'm not a hog farmer), but it's something to be aware of.


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## Legislator (Mar 27, 2020)

If you're willing to modify the frame you could likely fit 40mm tires.  

One way is to drill a hole in the driveside dropout and tap it for the derailleur hanger fixing bolt, which allows the axle to slide another 3/8" back to the very back of the dropout.

Another is to dimple the insides of the stays a bit more than they are, which is a bigger can of worms, as it often requires you to build or modify some tools.  I have a highly  modified C-clamp that I use for this that I made by cutting the ball end off a ball peen hammer, reshaping it to look more like a 'pill', brazing it to the fixed portion of the clamp, and then making a series of differently radiused wood blocks to support the other side.  Generally I find that even if you bolt a hub in to support the frame when I do this, it still throws the frame out of alignment, and necessitates a realign, but most Chicago Schwinns are a bit wonky anyhow, which looks to be the case with yours too.

Panaracer makes some amazing 38c tires though, the file tread Gravel King come in a number of different colors, and they ride amazing.  Only downside is that they aren't cheap, but they are high quality.


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