Cannondale Topstone Carbon — First Impression

For some time I have wanting to replace my rim-brake aluminum frame Cannondale Cyclocross “race” bike. Part of the problem with that bike was that with cantilever rim brakes it had little tire clearance, esp. near the rear chain stays as mud collected there. So I decided on the Cannondale Topstone Carbon. My reasoning for that model was based on the following factors:

1. Unlike many other gravel bikes, this one came stock with a nice low “front end” gearing of 46/30 instead of road-specific 50/34 like many gravel bikes have.
2. My one-and-only local bike shop is a Cannondale dealer, but doesn’t carry other major brands.
3. The stack height was “more than average,” which for a guy who is 6’3″ tall, is important.
4. The cost of Cannondale products are less than Trek and Specialized while typically provided similar quality.
5. Kingpin suspension which offers up to 30mm of shock absorption.

This bike, with disc brakes should have had more clearance…but man was I wrong! Their website says “Big tire clearance — comes with big 700cx37mm tires for grip and comfort, but has room for up to 40mm tires with tons of clearance. You can even put on 650 wheels with 48mm tires if small and fat is your thing.” I thought that with “tons of clearance” I thought I would be OK with 43mm rubber, but after installing 43mm Panaracer Gravelking SK “small knobby” tires and inflating them to 45 PSI the rear wheel would not turn at all! It rubbed against a fender bolt, just behind the bottom bracket. I removed the bolt and now the wheel will turn, but I can barely have 3mm of clearance between the bottom bracket and the front of the rear tire (I used an allen wrench to measure). Later, I took a Dremel and filed down (careful to not damage the carbon) the alloy ring gaining another millimeter and it now seems to be slightly better, but I still may go with a 38 or 40mm tire in the rear, instead of a 43 like I have there now. Ughhh. Buyer beware. Why do the bike manufacturers, when making a bike for “gravel and adventure” still think they are adhering to UCI cyclocross “race” regulations which max out at 33mm? Kills me. Is it because of chain line issues with the Q-factor of road bike cranks?

Eventually, I may get a 650b wheelset and run 47mm-wide knobbies for “those special days.”

Oh, one other thing…I’m 6’3″ tall (34″ inseam) and there is just enough stand-over height over the top tube. I am guessing that the BB height is higher than the average road bike to provide more clearance over obstacles and a nearly horizontal top tube maybe provides more clearance for frame bags. Not a deal breaker but something that was noticeably at first, but I am now used to it, after several long rides.

More later…I just wanted to quickly vent.