They are 135mm, but I used a chainstay spreader from my local bike co-op to spread them out a bit. I was still able to slide them on before I did that though, just took a few seconds of muscling the dropouts. Most early 90's (and many 80's) rigid mtb's will clear a 2.35 tire without a problem. Granted the clearances will be just a couple mm's, but if your wheels are true you shouldn't have a problem. I currently have 2.35 Nevegal's on this thing now with no problem. Measure it yourself if you're not sure! That's what I did. Just takes a ruler or some measuring tape.