Proflex 752 hack build

[Thias]

I'd imagine they ride quite similarly given the rear setups - both likely to suffer under pedal load.

See? That's the interesting part. The Scott has its rear swing arm turn around the bottom bracket. Literally. It makes for a funny (and quite brittle) bearing. But it also ensures that the chain tension doesn't influence the suspension. The distance between the rear axle and the bottom bracket is staying constant while the suspension is travelling. As opposed to the Proflex. There the swing arm bearing is (way) above the bb. So whenever the suspension compresses, the rear axle swings away from the bb. Or, if you think about it the other way around: If you press on the pedal, the chain tries to pull the rear wheel closer to the bb. That in turn is what people call pedal bobbing. Which doesn't occur with the Scott, because of the mechanics explained above.

Here is a picture of that scott bottom backet/swingarm bearing.

Mine was broken and I had do do some welding to fix it. (I made a build thread for that bike, too. There should be a link in my sig.)

Those kind of experiments that were actually done and produced and sold in the early to mid 90ties. I find that to be most interesting. I can't stop myself from babbling about it...

Long story short: Scott: No peddal bobbing. Proflex: I suspect quite some of it. Not too much, because of the small amount of travel, but still.

@MSYT That is a fantastic drawing.
Beeing a computer guy irl I try to keep my hobby analog, mostly. So no CNC for me

Also I'm one step further already.



Aaand done!

 

[markoc]

Ah, I didn't see the BB pivot as its hidden by the chainset in the pic.

Good skills on making a rocker.

Could you use a powerhanger on the central bolt and then route the cable direct to it (with a zippy on the seat tube) rather than having to run the cable to the seat stay pip? Would be a lot less convaluted.

 

[Thias]

Yea, I thought about that. But that wouldn't work I think. At least not with all types of cantilever brakes. Because I suspect the right side cable would come awfully close to the tyre.
I mean, the power hanger is basically the same thing but shorter and with 1:1 pull ratio. My hanger has a tad bit of lever advantage (is that even the correct term?) 2 : 2.5
Will be interesting to see if or how much of a difference it makes in brake point feel and brake lever travel.

Why I did the different ratio, you ask? Thats easy. The scrap Aluminium already had those 2 holes in it. So I had to make it fit as to not waste any material.

 

[MSYT]

@MSYT That is a fantastic drawing.
Beeing a computer guy irl I try to keep my hobby analog, mostly. So no CNC for me

Also I'm one step further already.

Thanks. I did 3D print a prototype but my printer isn't the most accurate... Still, it was a fun experiment (I'm still learning Inventor)

Looks like you've got it all sussed though. Increasing the ratio sounds like a good idea too! I'll keep an eye on this.

 

[Thias]

Did a little more work on the brake thingy. It's basically finished. Still needs filing so it looks less rough. But mechnically I think this will work.

 

[Thias]

Front brake basically sorted. Yea, I need a new set of koolstops at some point in the future. Just pretend to not see that crack, ok?


Next would be the drivetrain. Rear: DX - the special Version with save to the touch teeth rollers.

That'll be especially fun to clean. Would make for a good ASMR- Youtube video...

And then there is the front deraillor. As I learned not too long ago, I've been doing it wrong all those years. But I am able to learn and adapt.

 

[Chopper the ex Copper]

I know I'll be severely flagellated for saying so, but I'm not a fan of the Pronetoflex.

 

[Thias]

Blasphemie! He said it again!

... are there any women here today...?

... ok. To make it absolutely clear, noone is to throw any stones until I blow this whisle. Even if someone says... No. I won't fall for this trap.

Ok. I shall continue.



I have a feeling this should be some kind of record. At least on the continent. You Brits should have seen worse last week.


That should do it!

 

[MT62]

Well it protected the jockey wheels nicely!

(Another build thread that is fun to follow, great.)

 

[Thias]

Kind of difficult decision on the flavor of the crank. At first I thought it would be easy win for the black one. But seeing it now, I'm not sure. Seems kinda heavy. Maybe try a black seatpost, too? Or a silver chainring to make it seem less bulky?



Silver is looking good, I guess. But it's kinda booring?


Campa - ugly as it always seems to be...


Thoughts anyone?