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Old 04-10-07, 05:24 PM   #1
jur
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Making a Swift lighter

I think this one deserves its own dedicated thread. Since the swift is out of the box one of the lighter folders out there, let's see the ideas under one common heading so that future owners can refer to it for ideas.

I'm building up my Swift as my lightweight roadie and am considering every single bit very very carefully. Yesterday I made a drivetrain weight & cost analysis which I will post when I have a bit of time.

Other items that are currently under scrutiny, is the seat post and the steerer riser, and even the entire fork.
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Old 04-10-07, 07:10 PM   #2
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Gearing analysis:

Going by my experience on my CRX2, the lowest gear I had and occasionally needed was 31GI (gear-inches). The highest gear I had on it was 116GI. However, I pnly used this gear going downhill when I wanted a rest but still wanted to pedal, so just spinning legs but no effort given. I don't compete, so I don't really need this gear, and here is only a small amount of difference for me between pedalling or going into an aero tuck.

If I really want to put a big effort, I spin at perhaps 90RPM; with a 58Tx11T gear combination this gives about 40km/h (25mph), adequate for most cases. Higher speeds require higher than 90rpm, easily given during short bursts. Using a 11-34 cassette, the lowest gear is then 32GI, very close to what I am used to needing on the slopes. That small difference is negligible for me.

This leaves me in the clear to select a 11-34 cassette with 58T ring. The alternative is to use a road cassette, say 11-23, plus 2 chainrings 48T-60T, with a derailer which I would have to custom mount due to the large seat tube diameter.

Calculating the extra weight from the extra chain ring, flat bar XT shifter, cable+housing, front derailer, gives an extra weight of about 350g over the single ring solution, plus perhaps another $100 easily. All this for closer spaced gearing. The money saved could be put into XTR componentry, saving perhaps another 100g, making up almost half a kilo.

All this is weight weenie stuff, but it does make a difference if you're a keen climber. So I will go the single ring way.
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Old 04-10-07, 07:22 PM   #3
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As one point of reference, I'm going to paste the component spec. on my Swift from the main thread: Stock crank, brakes, brake levers, and seatpost; homebuilt wheels with IRO small flange 32h hubs, Sun CR-18 406 rims, Sapim 15 g spokes, Schwalble Stelvio 20 x 1.125" folding tires, Dura Ace 14t 3/32" cog (paired w/ the stock 52 ring), Speedplay Frog pedals, Nitto Dove bar (flipped), cheepo 120mm 10 degree rise stem, Terry Zero Y saddle, Minoura cage holder w/ Blackburn Switchback, UN73 bottom bracket, and sealed bearing Shimano headset. I think that's it. Weighs in at 19.5 lbs on my bathroom scale.

Right now I've got Freddy Fenders front and rear, plus a Nasbar front rack/bag on it; haven't weighed it in this config.

I too would be interested in fork options, not so much for weight, but to get a little compliance, if that's even possible with such short lengths.

Jack
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Old 04-10-07, 07:36 PM   #4
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Do you have more info on the IRO hubs?
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Old 04-11-07, 12:35 AM   #5
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Great idea for a thread.

I've been using the swift more and more (99%) of the time and my 700c bike is used to get mail and tow the kid in the tagalong (b/c it's the only bike with a 27mm seatpost).

I have replaced the crankset w/ 105 and put in an ultegra bb. Saved a whopping 100g from the stock config. I could remove the 39t ring, but I may want to use it for some sustained climbs. Switched back to the stock wheelset and derailleur. Huge 2lb savings over my internal hub setup. Bike weighs in at 23lbs/10.4kg. Hoping to break the magical 20lb barrier.

Things I've noticed, the steerer is a heavy steel thing. I need the entire length, but weenies should definitely cut to size. The long seat tube may be another weight issue.
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Old 04-11-07, 02:59 AM   #6
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@Jur. If you can get a Capreo cassette/hub you can change the sprockets and create a 9-32 spread. With a 54t ring this should give you the kind of widish range you're looking for with a single ring. I do have the weights somewhere, although I think I posted them on this forum last year...
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Old 04-11-07, 05:14 AM   #7
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Hello Jur


Since we are talking about XTR we can easily change for a "Dura Ace" talk or even "Campagnolo" talk. This time I will stay with the Shimano talk. First of all I would suggest 28 spokes 1.8/1.5, of course 451 mm wheel. As rear hub, Capreo hub + cassette, as front hub XTR or Dura-Ace, it's your choice. With a Capreo rear cassete you can assemble with a front 52 or 53 teeth chain wheel (and crank) Ultegra or Dura-Ace of course. This drivetrain gives you the confortable 3.0 to 8.8 gain ratio. The last 3 recomendations are Thomson seatpost, flat handlebar and ofcourse Swalbe stelvio tires.

Last edited by caotropheus; 04-11-07 at 05:23 AM.
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Old 04-11-07, 05:15 AM   #8
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The one thing that puts me off a Capreo is the non-standardness. Eg, I understand I can't use an American Classic hub, is that right? And when the cogs are worn, big expense to replace.
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Old 04-11-07, 05:30 AM   #9
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For the front wheel, I have a 16 spoke Am Cl Micro 58 hub, will be laced to a Velocity Aeroheat rim. I'm trying to get butted spokes. That will be my 'go-fast' wheel. I also have a regular wheel, 28 spokes Am Cl MTB hub laced to a Sun CR18 rim. I will probably put Primo Comets on all wheels.

For the rear, I haven't decided yet. I'd like to use Am Cl again, but the price...! Am waiting for one to appear on ebay. I missed a beaut one a few weeks back. The cassette will probably be an XT 11-32 @ 260g. XTR is 220g, that amount of saving is too small for me. The derailer will be a new Ultegra, I think 190g. I have used a Tiagra on my wife's 11-34T and it worked just fine, so I think the Ultegra will be OK on the 11-32.
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Old 04-11-07, 05:30 AM   #10
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How long do you thing that a cassete worns to the point it will be unridable? Good chain lubrification and chain repacement may help a cassette last for decades.
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Old 04-11-07, 05:33 AM   #11
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Quote:
The one thing that puts me off a Capreo is the non-standardness. Eg, I understand I can't use an American Classic hub, is that right? And when the cogs are worn, big expense to replace.
Yep, you have to use the Capreo hub so you're limited - also no weight savings there. As regards sprocket wear, I guess it would depend how often you used the 9t and 10t, but as they are both 100"+, (with a 54t) probably not that often.
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Old 04-11-07, 06:37 AM   #12
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Quote:
Originally Posted by jur
Do you have more info on the IRO hubs?
Here you go:
http://www.irofixedgear.com/index.as...PROD&ProdID=27

Weight Front: 213 g, Rear 290 g

I have no idea how these weights stack up. I bought 'em cause I prefer a nutted rear axle on fixed gear hubs, and because I've had good luck with Formula (identical to IRO) hubs in the past.

I would have liked to go with a lower spoke count than 32/32, but couldn't find any reasonably priced rims.

Jack
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Old 04-11-07, 07:49 AM   #13
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Quote:
Originally Posted by Fear&Trembling
Yep, you have to use the Capreo hub so you're limited - also no weight savings there. As regards sprocket wear, I guess it would depend how often you used the 9t and 10t, but as they are both 100"+, (with a 54t) probably not that often.
I think I'm happy with my choice of gear range, especially after touring Tasmania with my monstrously heavy R20 (17kg), loaded up with 20kg plus another few for food and water, and its gear range is 35GI-108GI IIRC. I would like a slightly lower low, and that high gear, while nice, is not essential. A 11-32 cassette with a 56T or 58T ring gives me slightly closer gears near the low end so a variety of slopes is catered for better than by the SA 8sp hub gears. I think I'm going to have my cake and eat it.
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Old 04-11-07, 07:59 AM   #14
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I have 2 seat posts in mind: 1) A Thudbuster from Thor (weighs similar to the stock Swift one!) for those touring-just-riding days, and 2) a 27.2 lightweight in a shim, probably a Thomson as caotropheus suggests. I understand they are uber-stiff and you get them in set-back options, something I need if I want to live out my aero posture dream on the go-fast days. Each option will have its own saddle as well, a B17 with the thudbuster and some ass hatchet job with Ti rails for the go-fast.
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Old 04-11-07, 08:08 AM   #15
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I think I'm happy with my choice of gear range, especially after touring Tasmania with my monstrously heavy R20 (17kg), loaded up with 20kg plus another few for food and water, and its gear range is 35GI-108GI IIRC. I would like a slightly lower low, and that high gear, while nice, is not essential. A 11-32 cassette with a 56T or 58T ring gives me slightly closer gears near the low end so a variety of slopes is catered for better than by the SA 8sp hub gears. I think I'm going to have my cake and eat it.
I agree, I couldn't talk myself into a Capreo cluster either...
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Old 04-11-07, 08:18 AM   #16
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Quote:
Originally Posted by JackJ
Here you go:
http://www.irofixedgear.com/index.as...PROD&ProdID=27

Weight Front: 213 g, Rear 290 g

I would have liked to go with a lower spoke count than 32/32, but couldn't find any reasonably priced rims.

Jack

I've laced 32h rear hubs with semi-radial patern ( 16 2-cross on the driveside and 8 radials on the non-drive) with a 24h rim, Several thousand miles later, still sweet! Matching front wheel uses 36h hub and 24h rim with balanced 2 lacing. Sometimes I have used the larger hole count on the rims, and filled the holes I didn't use with cute little plugs just to finish the wheel I wanted at the right cost.
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Old 04-11-07, 09:22 AM   #17
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Quote:
Originally Posted by jur
The one thing that puts me off a Capreo is the non-standardness. Eg, I understand I can't use an American Classic hub, is that right?
Correct.

Quote:
Originally Posted by jur
And when the cogs are worn, big expense to replace.
Well, you would have to get the tool and the cassette. But I don't think it is outrageous.

http://sheldonbrown.com/harris/k7.html#capreo
http://sheldonbrown.com/harris/tools...te.html#capreo

-G
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Old 04-11-07, 09:24 AM   #18
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Jur,

Have you thought about putting a double crank in the front?

-G
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Old 04-11-07, 01:50 PM   #19
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Quote:
Originally Posted by invisiblehand
Jur,

Have you thought about putting a double crank in the front?

-G
Yep, I did that with my wife's Dahon Yeah while on tour. At the moment I have a double crank on my Swift and I may retain the smaller ring, but my calcs indicate it's unnecessary.
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Old 04-11-07, 02:01 PM   #20
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Quote:
Originally Posted by Guy Retreau
Sometimes I have used the larger hole count on the rims, and filled the holes I didn't use with cute little plugs just to finish the wheel I wanted at the right cost.
What sort of plugs?
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Old 04-12-07, 02:45 PM   #21
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hey this is a great thread!

I posted earlier asking about alternative forks for 20" bikes and got not a single reply.

Since my Xootr is gonna be built for durability while also seeking reasonable weight loss, I'm not gonna be shaving grams. But I hate the generic unicrown steel fork... functionally fine but aesthetically boooorrrriiinnngggg. I have been looking longingly at the Answer Scythe Pro carbon blade forks. Unfortunately they are expensive and dont deliver much, functionally.

BTW since I'm building up a fixed wheel set with Surly hubs and CR18 rims, I dont need a front brake. Yay.

So I'm also looking at ti bars, ti or carbon forks, and prob'ly a custom seat post if I can source the right OD tubing. I've even considered cross drilling the stock seat post but not sure if that is a good idea. It'd sure look cool.

...anyway great thread, and I'll keep reading it with interest... except the parts about derailleurs n gears....
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Old 04-12-07, 02:58 PM   #22
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Quote:
Originally Posted by hulagun
hey this is a great thread!

So I'm also looking at ti bars, ti or carbon forks, and prob'ly a custom seat post if I can source the right OD tubing. I've even considered cross drilling the stock seat post but not sure if that is a good idea. It'd sure look cool.

...anyway great thread, and I'll keep reading it with interest... except the parts about derailleurs n gears....
You might still be able to find a Dahon carbon seat post (it was stock on my 17lb XX and a couple of other models)... it will fit a Xootr, at least it fits mine..

Bruce
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Old 04-12-07, 03:37 PM   #23
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Quote:
Originally Posted by JackJ
As one point of reference, I'm going to paste the component spec. on my Swift from the main thread: Stock crank, brakes, brake levers, and seatpost; homebuilt wheels with IRO small flange 32h hubs, Sun CR-18 406 rims, Sapim 15 g spokes, Schwalble Stelvio 20 x 1.125" folding tires, Dura Ace 14t 3/32" cog (paired w/ the stock 52 ring), Speedplay Frog pedals, Nitto Dove bar (flipped), cheepo 120mm 10 degree rise stem, Terry Zero Y saddle, Minoura cage holder w/ Blackburn Switchback, UN73 bottom bracket, and sealed bearing Shimano headset. I think that's it. Weighs in at 19.5 lbs on my bathroom scale.
Jack
Can I ask about the Frogs? How do you like them? Do they need constant oiling? And (sorry to bother you with this) could you give an estimate on how far they sick out from their insertion point in the crank? I upgraded to Egg Beaters, but my suitcase won't close unless I take one of them off. They are much longer than the salesperson told me they were. So, I'm considering swapping them for Frogs. I would use light actions, but I have SPD shoes.
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Old 04-12-07, 05:35 PM   #24
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I have a small tip for the weight conscious swift rider. I used to be involved in bike trials " hopping variety" and there is a class of bikes that use 20" wheels. I owned one of these ultra durable bikes, that weighted less than 18#, largely due to radially laced wheels with drilled rims, ultra light hubs ect. Best of all, the prices are fairly good for the weight. So check out MOD trials bikes, if just for the light rims.

PS. The front rims have a nice width to them and would give a nice profile to a Big Apple tire.
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Old 04-14-07, 09:23 AM   #25
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suspension seatpost

Quote:
Originally Posted by jur
I have 2 seat posts in mind: 1) A Thudbuster from Thor (weighs similar to the stock Swift one!) for those touring-just-riding days...
I'm interested in getting a suspension seatpost as well. I see that Thor stocks the new cheaper suspension seatpost for $40 and also the Thudbuster for $140. For potholes and cruddy pavement, is the Thudbuster is worth it?

Also, I'm pretty much at the red line on my stock Swift seatpost, is swapping in the Dahon post still advisable?

Thanks!

-Ari
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