Fork conversion from threadless to threaded?
#76
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Not sure how safe but it appears this is intended to convert 1 1/8 t 1" Headtube https://www.ebay.com/itm/1-1-8-to-1-...sAAOSwF1dUR0Zf
#77
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Not sure how safe but it appears this is intended to convert 1 1/8 t 1" Headtube https://www.ebay.com/itm/1-1-8-to-1-...sAAOSwF1dUR0Zf
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#78
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Okay, I think I have a solution: Bilenky Cycle Works in Philadelphia can braze on a new threaded steerer in place of the original threadless one for $125, which strikes me as very reasonable. The new steerer will have rolled threads. More about that in a moment. I assume that the powder coat on the fork crown and surrounding area will be toast after the work is done. It wouldn't be hard to have the whole fork refinished--there's a powder coat outfit near me that seems to do excellent work on bike frames--but knowing me I won't bother. I specialize in cosmetically imperfect bikes.
The Yellow Jersey shop in Madison would be willing to thread my threadless steerer for $60 per centimeter. Figuring a headset with a 40mm stack height, that's in the neighborhood of $250. Steerer replacement wins big in terms of cost, compared to cutting threads.
Also, based on my correspondence with Steve at Bilenky and Andrew at Yellow Jersey, I gleaned the following information, although it's still not as definitive as I would like it to be.
Andrew seems to say that cut threads are indeed smaller than rolled threads, and don't engage as well with the headset threading:
"I have filled in cut thread and recut where the material was intended for rolling or AH [not sure what AH is JV] and the cut thread engagement was poor. On our fine-thread bicycle formats, a few thousandths matters.
If it were a one inch I'd be more positive about it. It's a better design and we have better piloted tooling.
For 1-1/8x26 the format is ridiculously fine thread for the diameter and tooling isn't quite as positive for new thread centering.
The threadless column material is on the small side for a perfect cut thread. A good caliper and two forks will show that."
I guess all that makes sense. Rolled threads on spokes--which is the rolled thread that I think most of us are familar with--are obviously larger in diameter than the spoke itself. But the fine threads on a threaded steerer are so small in proportion to its 1" or 1 1/8" diameter that it's probably not easy to measure (hence Andrew's comment about a few thousandths mattering.) It would mostly be reflected in a somewhat sloppier fit of the headset parts.
In practice that might not matter much. If threading the threadless steerer was a lot cheaper, I might be tempted to take that route. But since a new steerer with rolled threads (per Steve at Bilenky) is half the price and gives a better end result, that seems like the obvious way to go.
The Yellow Jersey shop in Madison would be willing to thread my threadless steerer for $60 per centimeter. Figuring a headset with a 40mm stack height, that's in the neighborhood of $250. Steerer replacement wins big in terms of cost, compared to cutting threads.
Also, based on my correspondence with Steve at Bilenky and Andrew at Yellow Jersey, I gleaned the following information, although it's still not as definitive as I would like it to be.
Andrew seems to say that cut threads are indeed smaller than rolled threads, and don't engage as well with the headset threading:
"I have filled in cut thread and recut where the material was intended for rolling or AH [not sure what AH is JV] and the cut thread engagement was poor. On our fine-thread bicycle formats, a few thousandths matters.
If it were a one inch I'd be more positive about it. It's a better design and we have better piloted tooling.
For 1-1/8x26 the format is ridiculously fine thread for the diameter and tooling isn't quite as positive for new thread centering.
The threadless column material is on the small side for a perfect cut thread. A good caliper and two forks will show that."
I guess all that makes sense. Rolled threads on spokes--which is the rolled thread that I think most of us are familar with--are obviously larger in diameter than the spoke itself. But the fine threads on a threaded steerer are so small in proportion to its 1" or 1 1/8" diameter that it's probably not easy to measure (hence Andrew's comment about a few thousandths mattering.) It would mostly be reflected in a somewhat sloppier fit of the headset parts.
In practice that might not matter much. If threading the threadless steerer was a lot cheaper, I might be tempted to take that route. But since a new steerer with rolled threads (per Steve at Bilenky) is half the price and gives a better end result, that seems like the obvious way to go.
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Last edited by jonwvara; 03-16-18 at 01:27 PM.
#79
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I don't get why 1 1/8" standard decided to go with 26 tpi rather than the 24 tpi used for 1" and french. Are you going to have a 1 1/8 steerer brazed on and deal with the limited headset/stem options or go with a 1" steerer and use headtube shims to get a wider variety of headset/stem options?
I agree that the new steerer seems to be the way to go. Even with powdercoating the fork, it would probably come out cheaper.
I agree that the new steerer seems to be the way to go. Even with powdercoating the fork, it would probably come out cheaper.
#80
Senior Member
Cool. For $125 the new steerer is the way to go. Problem solved! I'd probably rattlecan the fork myself. Surly's are supposed to be utilitarian anyway, I think.
I checked and 1 1/8" threaded headsets are still pretty easy to come by. Ritchey sells one for ~ $15, or splurge on a Chris King for 10x that. There's a Tange in between.
I checked and 1 1/8" threaded headsets are still pretty easy to come by. Ritchey sells one for ~ $15, or splurge on a Chris King for 10x that. There's a Tange in between.
#81
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I love happy endings! Pics will of course be demanded.
#82
Calamari Marionette Ph.D
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Who knows why, but the BSC spec for 1⅛ was 26tpi and has been since 1949. It was used on tandem steerer tubes long before mountain bikes picked up the size. The reason I would guess is that a finer thread removes less material from the tube, so the threaded section stays stronger. That's probably more important on a tandem headset that has to carry twice the rider load on only a slightly larger diameter tube.