Plus-size blues

[jon_norstog]

Well, once more into the world of changing "standards" A current project is an update to my "elk hunter" - a kind of expedition bike. I wanted to continue this bike as a 29er but with the 3" tires. Turns out there are still very few 29" suspension forks out there that will accommodate the fat tire and the ones available - Manitoou Magnum and MRP/White Bros. Stage are available only with tapered steerers. The 44mm straight headtube looks like a beer can stuck on the front of a frame. The HJ jig I use won't accommodate tapered headtubes. Crap! Time to buy more stuff! Or else give up on using a boinger and build a solid fork.

jn

[jon_norstog]

More on the subject Paragon has stopped making tapered head tubes - "the demand wasn't there." Solidworks has them and I guess I'll use their stuff. If you are going to run pluas-size tires you are pretty much stuck with a "tapered" steertube fork. My own thought is "why does a bicycle need a bigger steering bearing than a Harley?" But I guess we gotta work with what the "industry" hands out.

jn

"Thursday"

[EricKeller]

Nova has a lot of choices in tapered head tubes right now. What's the issue with HJ fixture and tapered ht?

I agree with you about a 44mm straight head tube, although on something with 29+ tires it doesn't look so bad to me

[mmoore]

build with aluminum and the OS tubes blend quite nicely with the 44mm HT.

[mmoore]

"the demand wasn't there."

for guys like me that build one frame and work on doing another... the tapered head tube has appeal until you realize you need to buy two reamers to make it work. the reamer cost was the reason I still have a fairing tapered head tube in my box of random bits.

[jon_norstog]

Nova has a lot of choices in tapered head tubes right now. What's the issue with HJ fixture and tapered ht?

.....

The original HJ Universal jig has a v-grooved plate mounted to an arm that bolts down to the main plate. You clamp the HT into that groove, the center of which is exactly 2" above, and in plane with, the main plate. It only works if the HT is a true cylinder. I may pick up a used Anvil and lose the HJ, which has otherwise served me well making over a hundred frames. The new HJ Universal jig is completely different.

jn

[mmoore]

didn't a few people offer head tube fixture upgrades for the HJ jigs?

[steve garro]

I may pick up a used Anvil and lose the HJ, which has otherwise served me well making over a hundred frames.

jn

didn't a few people offer head tube fixture upgrades for the HJ jigs?

I did this.

See, it's not just the pucks & cones, it's that it's not designed for the ATC, BB drop, and TT length for modern MTB's.

Traditional road bikes, all the way.

Sure, I made cones & pucks and an adapter for Anvil dummy axles, but then the final limiter is that the HT rod is a proprietary diameter as it's a turned down 3/4" rod (I recall) that when fully extended is not rigid enough.

But, other then the limiting factors I mention, it's fine for every other kind of frame, tens of thousands of frames have been built on them, I built 100's on mine.

- Garro.

[jon_norstog]

What the old HJ jig did **really** well is keep the frame tubes in plane. Mine I got lightly used with the brake boss doohickey - best $900 I ever spent. I figured ways to make it work with 2" and mid BB shells, and got it to work on 20" BMX bikes which have a BB rise instead of drop. Etc. etc. The thing looks like it went through a house fire by now. Time to move on, I think.

jn