Afternoon,

Following on from my previous post of putting Hope pro2's on DT Swiss XMC130 forks I have realised after discussions with Hope that I must have a bulb hub (look very similar and use the same bearings) not a Pro 2.

So I have the 15mm converters designed for Pro 2 hubs which gerenally fit but the spacing is slightly wrong (bit too wide and need the spacing on the disc brake etc right). I a fairly competent machinist and have access to lathes and stuff so wondering if anyone had any thoughts as I do not really want to buy a new wheel just for the sake of it? Anyone know what the spacing are supposed to be on various aspects of the fork/wheel interaction, might be able to calculate them from there?

Any help would be greatly appreciated.

Cheers,

Chaz

what did Hope say when you spoke to them?

I'd be wary of machining up random bits of metal to try and bodge it, tbh.

Chap, i may have a set of 15mm adaptors for a buld hub as they were ordered wrong by my LBS.
If i can find them tonight il wack them in a juffy bag to you.
I will look tonight, fingers crossed. 😀

Hope said they had never made adapters for the Bulb hub to go to 15mm becuase the standard came out after they went to the Pro 2 hub and was not sure of the spacing.

Mr Bump – Are you sure they are designed for the Bulb hub as Hope said they never made them? I have the Pro 2 ones and they fit in the hub and look right but the spacing of them is wrong. Awesome if they you do have them through….

Thanks,

Chaz

I have just found myself in the same pickle! Hastily got hold of Pro 2 adapters only to find they don't fit. Any info will be good to know as I was going to do the same and machine them down.

I run bulb hubs on a 20mm axle. The first question I'd have is do the 20mm adaptors fit the fork dropouts in terms of diameter?

Is 15mm bolt through 100mm wide or 110mm wide?

If I had access to a lathe, I'd try making a sleeve to go all the way through stepping down the 20mm of the BULB to 15mm (ie, 2.5mm wall thickness). If the 15mm standard is only 100 mm wide, then just turn 5mm off the end of each oif the BULB 20mm adaptors.

And if it works, send me a set or two to try!

I may just have the information you need.

The pro 2 20mm adaptors are the same size (~18mm) so you can place them in either way round. The bulb has the same size adaptor as the pro 2 on the disk side (~18mm), however the non-disk side spacer is ~13mm, so like you say its a 5mm difference.
Its the non disk side spacer that is the different size, so if you could machine 5 mm from that sides spacer you should be sorted.

The measurements aren't super accurate as I don't have calipers to measure the lengths, but they are very close.

Just to throw a spanner in the works (possibly). There are two versions of the BULB hub with different axle dimensions. There's the 6 bolt version and ther old spidered version (which I prefer).

Ah ok, well these measurements came from a 6 bolt bulb and a 6 bolt Pro 2 just to clarify

Hmmm there is some good deduction there.

Right well I measured the forks and spoke to DT Swiss and the 15mm axle forks are 100mm (mine measured 101.2mm). So the disc side length is the same on the 20mm bulb and the pro 2 15mm at ~18mm yep (I will take calipers home to measure) so that means all we need to do is as Alan suggested take the remaining material off the other side to get it to fit? Right well the other point to consider is will the dishing on the wheel be right going from the 20mm spacing to these new ones (is the wheel datumed off the disc side and they go through to the other so just need to sort out dimension on the non disc side?)??

What I will do when I get home is take the non disc cup off, side the wheel on to the axle until it is up to the disc side and see where the rim sits currently and if it is right should just be case of machining the other side down right?

Thanks guys

As far as i can see, the spoke flanges on the hubs lie in the same position, so the dishing shouldn't be a problem, the difference is where the bearings are located, so there is more material to the outside of the non-disk side of the hub thus making the distance from outside of hub to fork leg less (i.e the 5 mm).
I don't think the dish will be affected at all.
Try the wheel in the forks with only the disk side spacer in and see how the wheel sits but I think you'll be fine

Well I will reserve judgment until I actually fix it but it could be a triumph of engineering prowess over the want to pay for new parts 🙂

Like I said before, I've not got any 15mm stuff to play with but if it's 100 instead of 110, shouldn't it be 5mm off each side assuming that each wheel has a common centreline?

Hi all,

I have had the same problem as above and today I solved it!

I have a bulb hub and wanted to use the Pro II 15mm converters, and alas the spacing problem occurs.

So after some measuring I worked it out and with some minor modification the fitment works with my Fox 831 forks.

I took the symetrical Pro II adapters and fitted the disc side to my Bulb hub.

The non disc side needed machining down,I took it to a local machine shop and they took 6mm off the outside of the adaptor.

Fitting this to the non-disc side the wheel slid into place and the brake spacing is perfect. The wheel is aligned centrally too, the wheel has been dished near flat on the disc side and normally on the other.

So it can be done!

Reading with interest
I assumed that the post from thebaker works with no issues.
Any further thoughts or findings

If I understand correctly what he’s done – no it won’t work as the bearings still have a 20mm inner diameter to suit the 20mm axle.

So if you just stick the 15mm adapters on and put the 15mm axle through without a sleeve or something to suit, it wont actually be contacting the bearings.

It would go together and clamp up and might even seem OK, but get on it and ride and bad things would happen, fast.

biscuit powered, wouldn’t the same happen to the pro2 hub? That has 20mm inner diameter bearings and sleeve too.

I don’t know what form the 15mm pro II adapters are – if it has some sort of sleeve that also fits in the Bulb, then yeah, it’ll be fine on the Bulb

Should work fine, as just mentioned, the bearings in both hubs are the same,and both have a similar type spacer in between.