Switching from Straight to Tapered forks (tapered head-tube)

jskrwyk

I recently got a new bike (Vitus Nucleus 275 V HT). It came with Suntour XCT forks, which I was looking to replace straight away and luckily found a good deal on a set of entry-level RockShox's. The head tube on the bike is designed for tapered forks according to both the spec from the company and an obvious visual look, however it turns out the Suntour's that were in it were straight forks.

All the guides I had read/watched about replacing forks talked about simply unscrewing the headset, removing the crown race from the old headset, putting it onto the new one, and screwing back together. This obviously isn't quite as simply. To begin with the crown race will be the wrong size I assume (?) and there is also a bearing cage that none of the guides really talk about. I assume that just goes back on top the new forks + crown race like it was before?

Oh and finally most of the guides I watched (some from GCN on YouTube) never mentioned remove/changing the star screw in the top of the fork pole. Do I just knock that out and push into the new ones or should I just buy a new one (they look to be dirt cheap).

Here are some images of the headset, head tube, and old forks.

EDIT:

I managed to get in touch with Vitus and they advised the sizing of the head tube was SHIS ZS44/ZS56 but that the current headset was a fixed 1 1/8" converter so it would need to be replaced. They recommended either the Brand-X Headset - 44-56IITS or Hope Tapered Integral ZS44 - ZS56, or simply replacing the bottom cup with either Nukeproof Mix & Match Bottom Head-set Cup or Hope Pick n Mix Headsets - Bottom Cup.

These sizes apply to all the Vitus Nucleus and Vitus Sentier 2018 range bikes as they all use the same frame.

cooldad

The crown race is designed for a specific headset. So a new headset will come with a crown race.

If there's already a star nut in the forks you bought, just leave it.

cooldad

just reread. Don't try and reuse a start nut. Buy a new one.

jskrwyk

cooldad wrote:

The crown race is designed for a specific headset. So a new headset will come with a crown race.

Does that mean I need to buy a new headset to fit the new forks?

larkim

The Vitus website says it is a 1.5 headset, so presumably there's a reducer in there to make it fit. This Hope one (http://www.chainreactioncycles.com/hope ... -prod71609) goes on a straight 1 1/8 fork and matches it up to a 1.5 headset with a 1.5 crownrace over the top of it. If that's the case, then the existing fork will have a correctly sized crownrace in place which you should be able to re-use on the tapered fork.

But I could be wrong! Best bet is to take it apart and have a look - and then post some photos!

The Rookie

You may....
The crown race on the fork will either be 'big' such that it fits the plain steerer and the tapered headset or a normal tapered headset using an adaptor, if its the latter remove it from the adaptor and fit it to the new fork.

Or the bike has a whacky headest to take a plain steerer and you'll need a new lower headset anyway.

OR its a 44mm frame which can be run plain steerer with a ZS44 lower or tapered with an external bearing, the photo's suggest to me its a 44mm headtube so you'd need an external headset to fit a tapered fork

Vitus website says its a 1 1/8" headset?
http://vitusbikes.com/products/nucleus-vrx-2018/

cooldad

larkim wrote:

The Vitus website says it is a 1.5 headset, so presumably there's a reducer in there to make it fit. This Hope one (http://www.chainreactioncycles.com/hope ... -prod71609) goes on a straight 1 1/8 fork and matches it up to a 1.5 headset with a 1.5 crownrace over the top of it. If that's the case, then the existing fork will have a correctly sized crownrace in place which you should be able to re-use on the tapered fork.

But I could be wrong! Best bet is to take it apart and have a look - and then post some photos!

He did and it looks like a 1.5 bearing on the bottom. Can't see if the reducer is removable.

larkim

My bad, missed the images link. Vitus website for this iteration (http://vitusbikes.com/products/nucleus-275/ - may actually not be the right bike, but that's where I was looking!) says it is a FSA Orbit 1.5B and then hover-over and it says Zero Stack (No 57B) 1 1/8). Headset 57 is a tapered one, but I couldn't find a "B" reference. Definitely looks to be tapered though, not 1 1/8. THis may be a better link to the spec on CRC - http://www.chainreactioncycles.com/vitu ... prod159719 - colour scheme seems to match the OP? Also says No.57 headset (though it also says it has a tapered steel steerer...)

Would be worth a clearer / better lit photo of the crown race area with the bearing cage lifted away so its clearer whether it is a crown race on an adaptor or just a large beefy crown race which does the adaption itself.

jb72

Agree. We need a photo of the fork / crown race without the bearings. i.e. is the crown race one piece or two.

jskrwyk

jb72 wrote:

Agree. We need a photo of the fork / crown race without the bearings. i.e. is the crown race one piece or two.

I managed to get in touch with Vitus and they advised the sizing of the head tube was SHIS ZS44/ZS56 but that the current headset was a fixed 1 1/8" converter so it would need to be replaced. They recommended either the Brand-X Headset - 44-56IITS or Hope Tapered Integral ZS44 - ZS56, or simply replacing the bottom cup with either Nukeproof Mix & Match Bottom Head-set Cup or Hope Pick n Mix Headsets - Bottom Cup.

These sizes apply to all the Vitus Nucleus and Vitus Sentier 2018 range bikes as they all use the same frame.

larkim wrote:

My bad, missed the images link. Vitus website for this iteration (http://vitusbikes.com/products/nucleus-275/ - may actually not be the right bike, but that's where I was looking!) says it is a FSA Orbit 1.5B and then hover-over and it says Zero Stack (No 57B) 1 1/8). Headset 57 is a tapered one, but I couldn't find a "B" reference. Definitely looks to be tapered though, not 1 1/8. THis may be a better link to the spec on CRC - http://www.chainreactioncycles.com/vitu ... prod159719 - colour scheme seems to match the OP? Also says No.57 headset (though it also says it has a tapered steel steerer...)

I think that's the 2015/2016 version of the bike. Those are the specs I had originally found when Googling but they have changed them since as they upgraded the frame on the Nucleus to have the same frame as the bike in the tier above. ChainReactonCycle's and Wiggle (where it was purchased) have been a bit useless with the spec. I spoke to them today to find out which headset to order and they advised a completely different (and incorrect) one from the one Vitus recommended. There have also been other inconsistencies like them stating the stock forks were tapered when they were straight.

The Rookie

Vitus is Wiggle/CRC's in house brand, so effectively they are disagreeing with themselves.