Thru Axle Diameter Issue

teisetrotter

Bought my first thru-axle DB bike last year. A cross bike ..... which I then set up with a road wheelset from Parcours.

Finally, I just bought a pair of Fulcrum Red 5 DB for cross racing. However, the thru-axles that came with the frame are too big. i.e. the diameter is too big.

Does anyone know if there is an adaptor or new type of thru-axle I need? Or do I have to start again and get wheels with compatable hub diameters?

For reference the Fulcrum Spec's state:
Front: HH15-100/HH12-100
Rear: HH12-142

Not that I have a clue what all that means!

Wheelspinner

In those specs, the “12/100” numbers refer to the Axle diameter/hub width.

The rear is apparently standard 12 mm diameter and 142 OLD (over-locknut distance) for the hub, or also the spacing between the rear dropouts where the wheel goes. This is a pretty common standard size these days for both road and MTB. There is an MTB specific version called “boost” which is 148mm OLD but still 12 mm diameter axles.

The front says either 12 or 15 mm axle - which is it? I don’t specifically know those wheels, but it’s possible the hub has interchangeable end-caps to accommodate either diameter. Both are listed as 100mm which is the standard front spacing between fork dropouts for both road and (most) MTB’s. Again, “boost” spacing for the front also exists on MTB at 110 mm in some suspension forks, but not on road or cross bikes.

Downhill race bikes have other sizes, but those are very specific to the intended use and the frames. Dirt jump type bikes also have odd ones like 135*10 bolt-up rears etc.

It sounds like your front wheel came with the 15mm axle and you very likely need the 12. Worth asking the seller if the end caps are supplied and if not, why? I’ve a few sets of wheels with front hubs which will adapt to fit a variety of fork fixings, from old QR, to 15mm and even 20mm axles with simple press-in end caps, all of which came with the new wheels.

teisetrotter

Ahh ha. Deep in the box there is an envelope ..... and in that envelope, there is a pack with a which says:

015mm THRU-AXLE - 100mm (code KITFCFA15)

I shall look into it and see if I can yet pass the idiot test on thru-axle DB stuff. Next rotor sizes and their fixings.

Many thanks for the tech translation.

teisetrotter

The idiot test now passed. Change the insert which pulls out, change with those in the envelope, and hey presto it fits a 15mm axle.