Kaito

Hi all,
I've run into a slight dilemma on the last stage of my Swift build, and was wondering if I could get some input from you all.

Over the weekend my carbon forks arrived, so I stopped by and visited the LBS today to talk to the mech. & see how smooth the install would go. Just a few issues though..the main, being that with the new forks are shorter than the stock ones by 3cm's..

We couldn't install the forks as the shop didn't have the proper headset, but we did remove the stock Swift fork & original headset to get an eye of how it would sit... and as mentioned above, it was "low ride'n" at the front...

The off set of the new fork wasn't too far off the stock fork & stem riser, so the mechanic said there shouldn't be to much difference in handling, but what do you all think? 3cm's lower seems kinda big to me.. & though new forks would lighten up the bike (forks are only 435grams!), I'm having second thoughts..if its gonna screw up the handling...the weight-savings wouldn't be worth it..
Is there an easy way to correct the geometry..?

Also, the stem riser (top steer tube? column?) is plenty long enough, but I either need a REALLY long spacer, or something to fit over the column to act as a spacer, in between the top of the head & base of the handle bar stem.
- Looks like about 30cm's. I was hoping to just trim & fit the Airnimal Joey stem riser that I have on it now, but it doesn't fit..The column is 1 1/8, but still no luck in squeezing it over the column..

Again, any ideas would be really appreciated..thanks!

Domo arigatou!
K.

jur

Yep I'm sorry to hear this, but you have run into the Swift forks problem. This has stymied me since the beginning. I have not been able to source a fork with correct crown-to-dropout dimension. Will that fork you have take the 451 wheels? I suspect perhaps not.

If you do fit this fork, I would suggest that you use a clamp to get the headset preload correct, and then just fit the Joey riser over the steerer tube. There is a headset from DiaCompe which has such a clamp. The function of the clamp is such that in a normal Aheadset fork, the stem can be removed without affecting the headset preload.

You may opt to get another Joey riser and take it to a machinist shop to very slightly enlarge the inner diameter such that it fits the steerer tube. That will still leave you with the original riser should you wish to swap back.

[edit]:

Alternatively, an aluminium tube of the correct inner diameter to slip over the steerer tube would serve as a long spacer would work with a normal Aheadset fork setup. I have done this on my R20.

I wouldn't go with a short fork for the simple reason I wouldn't like the looks of the sloping down top tube.

Kaito

Thanks for your input Jur-san.

I've done alot of digging around for a nice fork for the Swift, both in English, and Japanese, and when I found the Trigon fork, thought I struck gold, but alas...things aren't going as planned..

Good news there - The fork does accept the 451's. We even mounted the R556 calipers & with the pads all the way up, the brakes work too.

I'll do a search on the Diacomp headset you mentioned. It might prove to be useful.

Now I hadn't thought of that! The Joey riser just barely "doesn't fit", so I'm pretty sure it would be a simple/easy shaving inside the riser to get a good fit over the fork's steerer tube. If I do this, I'll reorder another Joey riser.. - in case I can't get used to the lower fork & decide to switch back to the stock fork.
~ Weight wise, I'd really NOT want to, but for handling & appearance, we'll see..

This is exactly what the shop mechanic suggested. He even dug up a scrap portion off a broken high-end Colnago carbon frame to see if it fit but it didn't.

Mmm...After we mounted the fork to the frame, this was the first thing that crossed my mind too...then I picked up the stock fork & was reminded just how heavy it is! & how much weight I'd be shaving w/the new fork!

If there was just some way for me to get the front of the bike back up to the same height as w/the stock fork...I'd be set!
For now, I'm going to keep carry through with the change out, but I might be back on the stock fork if I'm not satisfied..

Might have to research the lengths of the KHS & Gios mini-velo forks to see if they'd be a better fit.

Thanks again & I'll let you all know the outcome..
Rgds,
K.

sqynt

IMHO, a 30mm shorter axle-to-crown dimension will make a huge difference in handling, especially on a bike with small wheels. You will also lower your bottom bracket significantly.

I fitted a suspension corrected fork (extra 30mm a-to-c, 559 wheels) to a frame not designed for suspension in a deliberate attempt to kick out the geometry on my Xtracycle. It worked, but I noticed the elevated bottom bracket height immediately too. Not what I wanted, but is only a minor nit. Lowering it would have been bad though.

It you still decide to use that fork with a threadless headset, you can use the seat post clamp trick a-la Sheldon Brown's IRO (Google it). Use a seat post clamp. If you can't find one without the lip that prevents the clamp from sliding down the seat tube, you need to take a Dremel tool to it. You'll still need some way to pre-load the headset before tightening the seat post clamp. You LBS should be able to use normal spacers in conjunction with their headset press to do this with the fork in place.

Good luck.

jur

Does the LBS have an opinion on putting a spacer at the bottom? Would it be strong enough?

sqynt

If you mean below the race crown, what would the race crown be pressed on to? May be a custom machined, 30mm race crown? It would be pretty easy for someone with access to a lathe.

Kaito

That was the first thing I asked, and the mech. advised not to do that..
I'm not sure if that was because of strength issues, or because of headset holding issues..

Thanks for sharing sqynt-san.
I was afraid of that might be an issue...& unfortunately, its co$ting to find this out..Errr...

Looks like the forks are designed to fit mini-velo's with the really long headset tubes, like the Hammerhead, and Gios mini's.

If the Diacomp headset that Jur mentioned can hold everything together, then besides potential strength issues, I don't see why using spacers below the headset (above the actual fork) wouldn't work..~ but then, that's alot of piece-milling...

Domo~,
K.

Kaito

Dunno if I'm being persistent, or plain stubborn on changing my Swift's fork...prob bit of both..

I'm still digg'n for possible alternatives.
I was think'n maybe the forks for the Gios or KHS mini's might work, but I can't find any specs for their lengths. Just by looking at the pics on the manufacturer sites, they do look like short forks, similar to the ones I'm attempting to retrofit right now..

So far, just going off of pics, it looks like the Pacific reach forks just might work?
~ Same size wheels as I'm running on my Swift too..and they'd offer some cushioning..(they're not carbon, but still - gotta be lighter than Swift stock!)

* Would anyone with a Reach possibly measure their fork length & share?
Or point me in the direction of this on the net?
(distance from base of head to front hub axle)

Just trying to keep my options open for the best fit.

Onegai shimasu~! (please~!)
K.

Flitzer

Kaito,

Have you looked at the KHS series? https://www.khsjapan.com/index3/index3-2009.html
The fork of the P-20RAC may fit. There are other models but they all seem to steel or
aluminum.

Bob

Kaito

Yes, I've looked at the KHS possibility too & haven't written them off.
I'm going to try'n get fork lengths for the P-20RAC too.

Sidenote - A few weeks ago I was at the LBS & they actually had those bikes in stock. ~ They looked VERY nice!
(went back couple,few weeks later, and all three of'm were gone!)

Thanks!
Rgds,
K.

jur

SWMBO's Reach has a 33.5cm fork, my Swift 32cm, both measured the same way, axle to fork crown.

Kaito

thanks for that Jur!

Hmm....so right now I'm think'n, "which is better - 3cm's lower'n lighter, or 1.5cm's higher'n cushier.." (and probably slightly lighter..)

I'm not going to rush the selection this time, and will be gathering fork lengths to find the best fit.

Domo~,
Kaito

jur

Yes that is what I had in mind. But I am uncertain about the steerer tube handling the bending moment that is normally exerted at the crown.

A look at the properties of carbon fibre composite tubes may provide some of the answer.

sqynt

Wait. You mean that fork has a carbon steerer as well? I would be hesitant to do any type of spacer in that case. I had assume the fork has a cro-mo steerer, like most carbon forks.

Kaito

Yes, the steerer is carbon as well..
I live in a hilly area, with occasional bump's & jolts when going fast (50kms/hr+) downhill, so I'm hesitant to add anything that might lead to failure.

Mannn...this is look'n more'n more dismal..

Still going to install the fork once the headset comes in & see what we get..

Thanks for the replies!
K.

(Note to self: Carbon fork length from axle to fork crown: 29cm)

Kaito

Just sent an email to the manufacturer of this bike asking about the front fork details & if fork-only purchase was possible....fingers crossed for a fit, and fair price.

https://bike.gn.to/minimax.htm

PS- the headset needed to install short-carbon forks is in, but I'm dragg'n my feet on the install... : (

Kaito

Gotta reply back from the shop I posted above, but right now, they said they don't offer the fork separate..

So~ I had the (Trigon) carbon fork, the one I was debating about installing, installed this afternoon!

The install went smoothly w/the correct headset, and even riser-spacers.
The set up looks MUCH better than I expected, and the geometry doesn't look like its been effected ~too~bad..

Will post up some pics soon as I can!
K.

Kaito

Just attached a pic of the fork on the bike.

Since the fork install, I Rode the bike during lunch 25km's yesterday, and 25km's today, both with plenty of fast downhills, and long climbs.

In a nutshell, I'm relieved! - the bike's handling hasn't suffered a bit!
Still rock solid at speed, not twitchy, and the forks do feel like they dampen some of the road buzz.

Most notable difference is the weight of the bike! It's MUCH lighter!
The steel forks,plus the steering column are gone, so its both lighter, and very stiff.

It does look like the wheel-base has been reduced by 1~2cm's but again, for me, the difference in feel is very marginal.

Its a keeper! And I'm another step closer to completion of my build!


PS- The headset is the Shimano PRO, sealed bearing.
PSS- The Tektro R556's still worked. Just had to bump up the pads to the highest point.

sqynt

Any problems with pedal strike with the lowered BB?

4cmd3

Do you have any idea how heavy the steel fork is, or what the overall weight difference is?
Nice modification!
cheers

pibach

New fork is 3cm lower, i.e., ~1,5 cm lower BB. 451mm instead of 406 wheels compensate to rize BB by 45mm, thus it should be 3cm higher (!) not lower. Slim Durano tires again get it lower.

sqynt

If you mount 406 rims and 451 rims on your bike, both without tires, you would lower the bike by 22.5mm, not 45mm. "Normal" 451 tires will have a lower profile than "normal" 406 tires. The difference in effective rolling diameter is smaller than you think.

pibach

Oh, my fault: (451mm-406mm)/2 = 23mm difference.

Kaito

No pedal strike, and I don't foresee any.
Plenty of clearance - And I'm not about to compromise the safety of my bike.

All's good.
: )

Kaito

Just did some measuring w/a digital cooking scale in the kitchen.

Stock Swift fork only: 894grams

Airnimal steering riser tube: 267grams

clamps, shims, stock headset: 167grams

Carbon fork was advertised at 435grams, but I didn't weigh it prior to install.

Hope this helps some.
K.