Sorry, dumb question here....
I've read Sheldon's site, I've done multiple searches here. I'm just confused.
If I want to put wider tires on my 27" wheels for gravel roads, I can put 700c wheels on if my brakes have enough room to drop down.
BUT! I ride frames that have a tight standover because I have a long torso. As far as I can figure out, putting wider tires on a smaller 700C wheel will result in up to 2" of additional height?
Can someone just tell me exactly what to buy which will give me the most float over gravel but the least impact on standover? I'm touching the top bar as it is.... (luckily, I'm female).
The bead seat diameter of a 27" rim is 630mm, the BSD of a 700c rim is 622mm. That means a difference in radius of 4mm, which is the pertinent number regarding brake reach and standover height difference. So, assuming an equal sidewall height between tires, a 700c wheel will lower the standover height by 4mm (which is very little, of course), compared to a 27" wheel. Hope this info helps-
You will gain 4mm standover with a 700c wheel.
If you put a wide tire on a narrow 700c rim, you will lose some of that gain, but probably not all of it and certainly not 2 inches.
If you put a wide tire on a wider 700c rim you can have your cake and eat it too. You won't lose any of the gain and the combo will be a better, safer fit.