mooooo

I purchased Topeak Explorer rack for 2019 Cannondale Quick 7.

My problem is that provided screws won't fit inside the hole near rear wheel although screws are perfect fit for holes below the seat.
Anyone know the size of screws I need?

cobba

Any paint clogging up the threads on the frame?

mooooo

that seems to be the problem. I don't get it. why not put a pair of screws just like in other places. why leave holes?

Ironfish653

The upper mount screws go in to inserts in the frame (ie: holes)
You need to keep them closed (by putting screws in them) so that dirt/moisture/spiders don't have an easy way inside the frame tubes.

The mounts on rear dropout are holes through a solid metal plate, no need to seal them off. Also, a bolt that's long enough to go through the rack and the dropout may be too long when installed without a rack, and interfere with the smallest sprocket.
Finally, it is a cost saving to the mfgr. Why include rack mounting hardware with the bike, if not every owner will install a rack? (And racks typically come with mounting hardware) Yeah, it's only a buck or two extra per bike, but if you're making tens of thousands of bikes per year, it adds up.


To clear the threads on your bike, you need what's know as a 'chasing tap' It's designed to clear paint, dirt, light damage from a threaded hole (rack mount) without trying to re-cut new threads. Most likely an M5 metric thread.
You can get these at most auto-parts houses, or your LBS / co-op probably has one. Only takes a couple of minutes.

erf60657

Did you ever find out the size of the screw needed? I have the exact same problem!

Andrew R Stewart 

Money, lack of need and the lack of demand. Bottle boss (and to a degree some stay/blade rack bosses) are open holes into the frame's interior, the BB and such. Thus are best closed via a plug (as Trek uses for their rack bosses) or a bolt as with most bottle bosses. But drop out eyes are open holes with no interior to collect grime or water. The few pennies saved with each bolt not included (and the manhours to install said bolts) will add up over the many thousands of bikes that are produced.

Some might say this is penny foolish but how much more would one pay for a bike with those extra bolts installed when new? I suggest the market place has voted on the need and willingness to pay already.

I'll bet a beer or two that the dropout eyes are M5 thread. If this was a concern when the bike was bought a simple request of the retailer to chase the threads and install place holder bolts likely wouldn't have cost anything at the time of sale. Andy

erf60657

I will try an M5! Thank you so much.