possible donors on CL

[Clydesdale]

Well I missed out on the Trek Y3. So if you don't mind, can you take a look and tell me if any of these might work? Without a kit in hand, I can't really judge what frame characteristics are more compatible than others...

Thanks!

Trek 6500
http://images.craigslist.org/5V35X05S03n03k03pbbagbafa8055f632186e.jpg

Trek ???
http://images.craigslist.org/5V05Y65U13nc3k93m0balcd4b3f2a15581fbe.jpg

Trek 820
http://images.craigslist.org/3pf3o53lf5Z65U25P2b9g1527da9002531fd2.jpg

 

[Clydesdale]

update: never mind

After finding a Y3 in excellent shape, it looks like the conversion kits won't work well for tall folks, i.e. the bottom bracket will end up way too low at full extension. Bummer.

 

[John Tolhurst]

Way too low? According to

Way too low? According to what requirement?

 

[Clydesdale]

Well, I'm looking at the

Well, I'm looking at the pictures of other conversions and the conversion kit itself and with my xseam (48") that would put the BB too low for my taste. I was hoping to be able to have the BB even with the seat pan or nearly so. But because the conversion kit's chainstay length is fixed, as the boom is extended, the BB simply rotates forward and down. Forwards is great, down not so much.

It'd be cool to have an extension that could perhaps fit between the end of the chainstay and the BB to create more sizing configurations. I understand the problems with that approach at this point, it ain't going to happen (for sound business reasons--ROI!).

I was hoping to build a conversion to ascend the learning curve for riding MBBs in anticipation of getting a Silvio or Vendetta for fast centuries and brevets. By already being comfortable with the MBB paradigm, test rides on the S and V would yield better information for me.

 

[John Tolhurst]

I see, yes.
A conversion bike

I see, yes.
A conversion bike will give you the taste and skills you need to understand what a Silvio or Vendetta would bring you, even with a low BB.

 

[Patrick Bateman]

I had to hack up my

I had to hack up my conversion kit for the same reason. I'm 6'3" tall and the cranks were way too low.

Here's what I did:

#1 - cut the tube in half (I think it's called the chain stay?)
#2 - inserted an alumnum tube *inside*. The tube was covered with gorilla glue. From what I've found, Gorilla Glue is as suitable for bonding aluminum to aluminum as epoxy is

The pic above shows what it looks like. The bike is still a 'work in progress'

If you decide to do the same thing that I did, here's a few tips:

#1 - get a pipe cutter from the hardware store. It eats through the tubes and makes a nice clean cut. Don't bother using a saw, a pipe cutter does it better

#2 - use an aluminum tube that will 'sleeve' the whole length of the chain stay. It's stronger and it creates a long surface for the glue to bond to

#3 - speaking of glue, use plenty of it. One one of the chain stays I didn't use much Gorilla Glue, and the joint slipped. Since the whole tube is sleeved, when the joint slipped it was unventful, it's not like I crashed or anything.

#4 - I reinforced the sleeve by inserting dowels perpendicular to the chain stay. Basically I drilled holes perpendicular to the chain stay, inserted a dowel covered in gorilla glue, and then wrapped the whole thing in electrical tape to keep the glue inside the joint while it dried

MAKE REAL SURE YOU MEASURE BOTH SIDES. If one side is longer than the other by even a centimeter, the wheel won't 'track' straight, and the crank will be canted to one side.

Of course, since I'm very sloppy, this is exactly what happened to me

And as always, never take any advice from a Cruzbike rider whose bike is nicknamed 'the deathtrap'

 

[Patrick Bateman]

another try at the image

another try at the image

 

[nerys]

I am also tall 6'4" (and

I am also tall 6'4" (and heavy) why is the crank position important? what does it being higher or lower actually "DO" in the end?

what is xseam? is that like crotch to foot or something ?

 

[John Tolhurst]

x-seam (search it) means sole

x-seam (search it) means sole of foot to the back of trouser belt when seated with your leg straight.

 

[Jake]

Inserting a chainstay

Inserting a chainstay extension tube (as Patrick Bateman has above) seems a bit drastic (although this is what the Silvio chainstay extender does).

How bad does the handling get if the forks are not reversed, as this would add a few inches to the effective length of the chainstay, (and allow disk brakes)?

Or move the seat back, although this would effect center of gravity and possibly limit seat angle.

Jake

 

[John Tolhurst]

How bad?

"How bad does the handling get if the forks are not reversed"

Bad enough. Trail is really important, on every bike and every motorbike. The front wheel must have a little bit of the supermarket trolley wheel about it. It needs to naturally pull straight. That is why it set to trail (behind the line of the steering axis to the ground).

 

[Jake]

Aero

"why is the crank position important? what does it being higher or lower actually "DO" in the end?"

In a word aerodynamics. The more horizontal the rider (ie bottom bracket high, seat reclined) the less wind resistence is produced. This is most noticable at high speed, hence the performance Cruzbike (Vendetta) has a very reclined position, whereas the more comfort orientated models (Sofrider, Quest, Conversion Kit) have a more upright position (less aero, but easier to learn to ride, better view of road, more visable in traffic, less neck ache).

The posters on this thread are looking for ways to make the conversion kit more like a performance bike - ie raise the bottom bracket, particularly for tall riders as the sizeing adjustment mechanism does not allow for independant adjustment of leg length and bottom bracket height. This problem has been solved for the Silvio by the addition of a chainstay extender.

Jake