Rychtarski General Purpose Bike

Hi all!

I started a new project some months ago with the intention of building myself a bike that could take me to gravel roads, occasional century rides and light touring. After a thorough investigation of today's frameset market I came to a conclusion that of all the candidates none would tick all my boxes. What to do? Go custom. I've been in touch with Tomasz Rychtarski changing ideas back and forth, presenting requirements and now it looks like all the major details have been discussed and decided upon. Before I go full custom I wanted to hear your opinion about the decisions we've made just to check if everything makes sense also to the big public.

I'd like the riding position to be quite relaxed and the bike itself to be responsive and fun but also predictable enough at the same time. The bike is supposed to have tyre clearance for 35-40 mm tyres with mudguards and also mounts for rear and front racks. Tubing is going to be Columbus Zona with a MAX fork. Disc brakes are of course nice! I've thought about full internal cable routing - any thoughts?

Tomasz was concerned about sufficient toe clearance with mudguards (front-center 599 mm). I've spent more time wondering about balance between front and rear ends. How do suggested chainstay length and trail for example work together? I really don't want either end to ride or act in a completely different way.

Finally here's the planned geometry. The guy is supposed to be me and have my body measurements.

590 stack (plus headset stack) and 379 reach .. I guess we have normalised T-rexes with gravel bikes now ..

my 2 cents; 32mm 700c tyres plus guards is the sweetspot or 650b and 38mm, the latter might reduce the toe overlap and reduce the wheelbase.

Sweetspot: the fat tyre benefit starts falling off after 32mm (700c) IMO and it really hampers the geo esp at your body dimensions (similar to mine)

425 chainstay length seems ambitious for what you are asking atm.

PS: Just buy my 54cm Diverge with 650b wheels.

Slacken headtube, increase rake on fork, 650b x 38 and you'll get more wiggle room.

Chainstay is actually 430 but Mr R has marked it incorrectly. I’m planning to use Ortlieb Sport Roller City panniers which are supposed to be quite compact. Should have enough clearance at the back.

How is he planning to get a 35-40mm tyre into a MAX fork crown? I would have thought that the width would be narrow and the fork legs wouldn't pass such a wide tyre.

There’s a 55 mm wide MAX fork crown available. That leaves about one centimeter on each side between tyre and fork leg depending on the exact tyre width.

425mm chainstays + 700x40c tyre + mudguards + front derailleur is very ambitious.

Wot Matt says - 50mm offset fork plays nicely with 72 HA. Though the (presumably) lugged fork crown and blade length largely dictates this - guessing it's an offset crown for straight blades? Maybe longer reach and slightly shorter stem is also an option for increasing FC and eeking out a bit more toe clearance?

...or go with 650b and not worry about having to make large volume 700c fit into a confined space.

Ignore what @amey says about wheelbase - not important given the context of the bike.

Thanks for all the comments so far! I always forget to mention some critical details. @Alb it’s going to have a 1x setup at least for time being so no need to worry about front derailleur clearance.

As you can see from the geometry drawing the toe overlap problem only exists when mudguards are used. Also my current bike has less clearance and I can’t remember it causing any trouble even at slow speeds. Perhaps the wild tarck bike years weren’t for nothing after all... It may also be that I’m just justifying my bad decisions and bike designing skills but what the heck. Frankly it seems that similar frames and bikes in my size usually have front-center measurements between 595 and 610 mm so it’s not all that bad after all. What I’m more concerned is if 430-600-65 (cs-fc-trail) lead to a potentially balanced ride and steering.

What tire size was used in the drawing - 35 or 40c? IMHO going custom is the ideal opportunity to design-out OTP-associated niggles like toe-overlap but each to their own.

If you go for 35mm tire + guards you'll be able to squize in 40mm tire without mudguards. This would also eliminate or reduce toe overlap. That’s how it works on my touring bike and although riding on 40mm tires is fun I felt like the steering was compromised a bit. For a long tours I run 35mm marathons plus and guards and never had to change a tube.

@Pawlus this is exactly what I have in mind!

Some have suggested a 50 mm rake fork in exchange for a bit more toe clearance. I believe it’s doable but in that case trail would be less than 60. If I’ve understood correctly 57 is supposed to be the neutral amount of trail. For some reason a large portion of adventure/gravel/do-it-all bikes have about 65 mm trail. If more trail equals better high speed stability why do so many bikes in this segment (Genesis CdF, Shand Stooshie and Stoater, Mason Bokeh etc.) have such high trail even though they are perhaps otherwise more suited to medium speed riding duties?

So we tweaked the geometry a bit (head angle now 71,5 degrees and fork rake 50 mm) and managed to stretch front-center by 10 millimeters with only -2 mm change in trail. Looks like that solved the toe overlap problem.

It’s now down to two decisions:
1) 31,7 vs 35 mm down tube
2) head tube vs. down tube cable guides

Is a smaller diameter tube more resistant to dings even with similar wall thickness? Would a 35 mm down tube on a bike like this be an overkill for a 75 kg rider and add excessive stiffness?

Head tube cable guides look nicer in my opinion. Is there a practical reason to choose them over down tube guides or vice versa?

Head tube cable guides look nicer in my opinion. Is there a practical reason to choose them over down tube guides or vice versa?

Down tube stops are a hangover from when the shifter mounts were adapted, with the advent of integrated brake lever shifters.

If the stops are mounted too high on the head tube the cable could foul the DT, but the frame builder should be aware of that.

Go head tube with stainless adjusters