Dahon Jetstream conversion

[cwah]

I'd like to add better suspension on my Dahon jetstream, currently it's not fun when I go through small potholes at high speed.

I want to do like this guy:

I've never changed the front fork before, so a bit of advices is required. Can I use this front fork?
http://www.ebay.co.uk/itm/Suspension-bike-front-forks-1-8-threadless-Ahead-100mm-Travel-/281313479338?pt=UK_sportsleisure_cycling_bikeparts_SR&hash=item417f970aaa

How do I know if it's compatible?

 

[Cyclezee]

Lateral thinking, get a bike with bigger wheels or ask the council to kindly fill in the potholes

 

[cwah]

Lateral thinking, get a bike with bigger wheels or ask the council to kindly fill in the potholes

I'll probably stick with 20" wheel even with bigger bike. Because I thrill acceleration

 

[Arbol]

Mini velos go in that direction.

If you have disc brakes, AFAIK you could go with 20'' wheels in a 26'' MTB.

 

[superDove]

The 24" eclipse from Tern doesn't look like it folds that much bigger than a 20" Dahon. Might be a good compromise for foldability, ride and acceleration.

 

[Willber G]

The 24" eclipse from Tern doesn't look like it folds that much bigger than a 20" Dahon. Might be a good compromise for foldability, ride and acceleration.

Here is a Tern Eclipse. You won't get much acceleration with the size of that chainwheel.

 

[Arbol]

cwah, if you want a bigger, foldable bike with good front and rear suspensions and 24'' wheels are small enough for you, you could take a look at the discussion between flecc and myself at:

http://www.pedelecs.co.uk/forum/threads/who-likes-crank-drives.17485/page-3

starting at page 3.

Summary: a Kona Cowan DS (or any other urban assault bike with BB = pivot point) could fold its rear wheel using the Brompton / Ori / Birdy method, and having a belt in singlespeed mode. Possibly (this is not discussed there) a rear suspension bike with BB different from pivot point could also be folded in this way with normal chain and gearing.

I know you often look for "original" solutions. This could be one.

I would like to try it, but I still have not found a way to solve the major problem of this solution: to accomplish to "break" either the seatstays or the suspension link in a way to fit the mechanism that allows Brompton / Ori / ... to fold the rear wheel, such as:

at 1:05.

It seems this mechanism is robust, since many different bikes use it, and I have never heard about wrong functioning.

Probably the bike I suggest would need two of them, because there is no point at the seatstay / suspension link level with only one tube. But that should not be a problem.

If you like the idea, and you know somebody who could fit such a mechanism in such a bike, please let me know, we could share costs.

 

[cwah]

BMW has such a bike:

http://www.foldingcyclist.com/BMW-folding-bike.html


But it seems that the bike is overpriced and not sold anymore...


Maybe another way to solve the problem is to get a Mezzo bike and extend the rear to allow bigger wheels. Then mod it to add front suspension.

 

[Arbol]

A mezzo or even that BMW bike would be possible, yes. But the problem of having the batteries protected inside a box remains unchanged. I believe this is the real problem of ebikes (at least for my usage, of course).

Instead, if I could do what I have said (having the Brompton / Mezzo "break" of the seatstay in a rear suspension bike), I could ask a guy close to my home to do something like this, as he has done in the past:

From:

To:

And he is not exceedingly expensive, I believe.

 

[Arbol]

Another interesting BMW is the Q3, at the bottom of:

http://www.foldingcyclist.com/BMW-folding-bike.html

cheaper, with no rear suspension ... but interesting nonetheless. Just with a rack at the seatstays, it could roll when folded ...

 

[cwah]

Yeah that looks complicated. I don't know anyone able to do that... If I knew, I'd have already modded my bike several times lol.

Can't your friend who does welding help you on this part? If you manage to find any way to sort that out, count on me to buy a bike

 

[Arbol]

Yes, maybe he could. I will ask.

 

[cwah]

I realized the normal commercial dropout are definitely not enough with my bike torque.

Left torque arm:

Right torque arm:

I have these 2 torque arms strongly attached... and I realise that the axle was widening through the 2 torque arm holes??

Damn it's only 2.8KW... I need stronger torque arm. I'm thinking of drbass ones...

 

[Deleted member 4366]

I had the same problem with those ones. The ones from BMSBattery are much stronger and a better fit.

 

[cwah]

I damn D8veh, you should have posted a review. That would have avoided me to buy these cheap torque arms

I'm thinking to get the "best in class" torque arms from Dr. Bass:

The axle is 14mm wide right?

 

[cwah]

These are the dropout washer from BMSBattery:

These are made of soft steel, maybe mid steel. They break in 2 really easily. Better not having them.

 

[cwah]

My motor is making strange noise

Is it the clutch?

 

[Deleted member 4366]

It doesn't sound good. I think you'll have to open it.

 

[mountainsport]

Another interesting BMW is the Q3, at the bottom of:

http://www.foldingcyclist.com/BMW-folding-bike.html

cheaper, with no rear suspension ... but interesting nonetheless. Just with a rack at the seatstays, it could roll when folded ...

Arbol you surely need a good back to ride this bike.

MS.

 

[Arbol]

Arbol you surely need a good back to ride this bike.

MS.

Why is that?