troysmith80

I've built my own longbike, and an actual xtracycle for my wife. We're beginning to think that they're longer than we need for 90% of the time and considering something a little shorter. I'm not sure it really makes any sense to go shorter, because the length isn't much of a problem, but i just like messing with stuff!

Anwyay, i'd noticed that the Kona Ute and Trek Transport appear to be significantly shorter than the Big Dummy or Xtracycles, just judging by the apparent distance from the rear wheel to the seat post.

I decided to collect as much info as i could find from the manufacturers websites and put it in a table for comparison. The relevent info is primarily wheelbase and chain stay length. And i added a row for a computed value that is how much longer the chain stay is than that of a supposedly average bike, with a 44cm chainstay.

Below is the info for your reference. It's interesting to note that indeed the Big Dummy and the Sun Atlas (and i suspect the Yuba Mundo as well, though i couldn't find numbers for it, however it's wheelbase is even longer than the Sun) are indeed about 20 cm longer than the Ute and Transport, and even a couple cm longer than an Xtracycle.


(Updated to correct for 700c wheels on Kona, update CS lengths, add home made bikes)

sjt78

The Konas use 700c wheels...not sure how that affects your calculations.

Sixty Fiver

My DIY extrabike is 62 inches / 155 cm from axle to axle... I would need to measure the chain stay and total length to make other comparisons to commercial bikes.

troysmith80

sjt78, thanks for that! I'll have to update the spreadsheet. I thought they were all 26" bikes!

SixtyFiver, probably the easiest and most useful measurement is from the original dropout to the new one. That's basically the added chainstay length, right?

My home made longbike, using a walmart full-suspension bike rear triangle as an extention, is about 43cm from the original dropout to the new one. Wheelbase is about 160 cm (it's a loooong bike, it was a long cruiser style frame, and then i extended it).

troysmith80

I'm having a little trouble determining what "normal" chainstay lengths are for 26" and 700 frames. The thing is, what sort of frame is "normal", i'm trying to pick the bike most like the cargo bike, but that is not extended. The strange thing is, the 700 frames appear to have shorter cs lengths than the 26" bikes, how is that possible?

For 700 wheels, it's only the Konas that we're looking at. So, for reference, i looked at the paddywagon and bandwagon, their CS are about 41cm.

Sixty Fiver

Measure from the bottom bracket to the rear drop out to get the total chain stay length.

Mine... if you have not seen it.

sjt78

As for the 700c bikes you were looking at, the paddywagon and bandwagon, those would not be average as they have track geomety so a shorter wheelbase in general. For example, many cyclocross and mountain bikes come with a 42.5cm CS. I'm not sure if you could find an average CS across bikes as bikes designed for different activities will differ in CS and wheelbase.

sjt78

Sixty Fiver...is that an 1 1/8" quill stem you got there on your Norco? If so, I've been looking for a stem like that for my commuter bike. I even posted in the C&V forum to see if anyone there knew where to find such a stem. I'd rather avoid getting an adjustable stem if I can.

Sixty Fiver

It is a 1 inch quill... I do have a 1.125 threaded adjustable quill if you need one and know how hard these can be to find as they were not offered for very long.

sjt78

Thanks for the offer. I'm not sure I want to go the adjustable route. Most of the ones I've seen or heard about are not tight or don't stay tight for very long. Another option I have is a steerer tube adapter along with a threadless stem.

kevbo

700c bikes tend to be roadies with the rear wheel as close to the seatpost as possible, and fairly vertical seatpost angles at that. 26" tend to be MTBs or cruisers, with more relaxed seatpost angles. Also, they need to clear wide tires, so the chainstays need some distance to neck down to the bottom bracket...this is also needed to clear the chain rings.

troysmith80

Ah, that all makes sense, thanks kevbo.