29er fork issues/options

[ishaw]

My latest build is throwing me various curve balls. The latest is fork/frame clearance.

I've fitted an internal hope 1 1/8 headset and slotted the forks in. However, the adjuster dial hits the cable guides on the down tube. Obviously things have gone wrong if I have to turn that much, but want to remedy this as I'd rather not ruin a lovely ti frame in the event of an accident.

I'm thinking that I should run an external tapered bottom cup, as this will (I think) sort the clearance issues out, but my fork is straight 1 1/8 so won't work with this set up. Even if I were to use a reducer crown race, I don't think I have enough steerer spare.

Headset is a hope one. What is the correct model for the bottom cup that would allow me to use a tapered steerer?

Is it worth trying to source a different csu for my forks, 29er sids or sell them and buy a new set? I do have a spare set of 27.5 reba forks with a tapered steerer, but I've no idea if they would be compatible. Anyone know? I've read various online posts about offset and compatibility but I'm none the wiser as things appear inconclusive.

Any help and advice gratefully received as I'd like to get the build done over xmas and get out riding in the new year.

 

[scant]

theres a lot of variables here. the external lower cup should sort out the downtube clearance issue. if you lower the fork to the imaginary depth of the cup you'll be able to check clearance. hope external cup with crown race is around 14mm <i just measured 1>

theres several different sizes of external lower cup depending on the internal diameter of the frame. cane creek & fsa both make decent lower headset cup & crown races that are often available separately for sensible money
https://www.hopetech.com/_repository/1/ ... -Chart.pdf

unless you're running a tiny size 29er tyre, closer to gravel grinder than mtb, then the tyre wont fit the fork lower brace & may bottom on the crown with a 27.5 inch fork

hope that helps

 

[ishaw]

Re:

Cheers. The other curve ball my build has thrown is tyre clearance. I cant run a 2.4 conti trail king and the frame clearance is non-existent but the tyres look massive when inflated so suspect they are a huge volume tyre. They fit the forks though. It's a bit annoying as I bought 4 tyres after confirming with the frame manufacturer what tyre size would work, back to the drawing board there I think.

Back on topic, I'd like to get a hope lower cup, I think I need a z44, at least that's what the internal one is, just need to work out what the external equivalent is so I can keep the top cup, though not averse to a new complete headset if it makes more sense financially.

Might scour the sales for a new fork, though the current one is like new so a shame really.

 

[retroaddict]

Re:

Do a franken fork

 

[jonnyboy666]

Re:

with the headset cup you'll need a EC44, you mention a z44, i think you mean ZS44, 44 refers to the headtube dimension, the ZS is zero stack and the EC is external cup, if you are changing to EC44 you will need a different bearing as well as the cup as well as the reducer crown race.

regards the fork steerer, if it is too short, get on to Dave at RSF suspension to find out if he can replace the steerer, he might be closed for xmas now but he's awesome, he can press out old steerers and refit new ones, same with fork stanctions on some forks, he replaces them with ND tuned steerers, top bloke, i use him for all my shop work when it's more sensible to send the fork to someone, he's better than sram tech, tf tuned or silverfish (formerly mojo) and he charges less than they do.

 

[ishaw]

Re:

Cheers, not up to speed with the modern stuff, thanks for the help.

I've used rsf before and was very happy with the work and cost, so may go that route.

 

[firedfromthecircus]

Cut off the cable guides and run it singlespeed is the obvious answer!

 

[ishaw]

Cut off the cable guides and run it singlespeed is the obvious answer!

Or a stupid answer.

 

[ishaw]

Re:

Darn, the spare csu I have is also too short for the frame so a new csu or fork looks to be on the cards if I go with running an external cup headset.

Seen a new one for £70 which seems an ok price. My sids are dual air and I've never quite got my head around the sid a, b xx compatibility, nor solo air vs dual. Before I take the plunge, are there any experts out there who can help me understand the differences between the csus so I dont buy one that doesnt work with my current internals.

Cheers

 

[d8mok]

Re:

What size is the headtube ? Taper or non taper.

How modern is the frame. Is it designed to run a external cup?

Is the fork tapered ?