26” Endurance Ride Cunningdale build.

[doctor-bond]

Thanks for some great info (That gear insight needs a sticky!) I’ve been digging the bikerollingresistence site - it really cuts through manufacturers’ hype.

On tyres, I’m thinking, use resistance measurements as a way of getting relative values (in a given condition, tyre x vs tyre y), then actually try out a shortlist in real-world conditions. (Luckily, I’ll probably be saving a £95 entry fee so can splash on a coupla pairs ).

I also want to understand how resistance translates into extra riding effort. A cursory google suggests there are equations I can try and understand, and that, over big distances, it can make quite a difference.

In terms of feel from real experience, my benchmarks are Vittoria Pave Tubs (25mm), Corsa Open Pros (28mm, 25mm) Jack Browns (33mm Rivendell designed Panaracers). These all roll well and feel great on my road bikes, and give me confidence that relatively narrow tyres can cope with uneven roads (born of some fiendish c-road asset management here in East Yorks).

I’m also sold on latex tubes. My tubs are built round these and at higher pressures, latex performs as well as tubeless and is as light (there‘s a great bikerollingresitance article on it). And in 26 flavour, the narrowest latex tubes I can find are Vittorias at 1.7”.

In terms of rims, I’ve got Wolber AT18s, Specialized BX21s and Ritchey Vantage Comps. All pretty narrow. Will start with the Specialized’s, go to the Wolbers and then try the Ritcheys, which are a bit wider But need building.

All of which leads to the following shortlist:
Schwalbe Marathon Greenguards 1.75 with latex Tubes. (Supremes dropped for now because they are 1.6” and not latex compatible. 2.0 is too wide.)
Schwalbe Fast Fred lights (1.8ish old Skool sub 500g hybrids) with latex Tubes. Have a NOS pair to play with.
Panaracer Pasela PT 1.25” with whatever skinny tubes I can find (prolly Specialized butyl).

Next thorny issue: frame fit, angles and handling differences between road and MTB frames. Let‘s get intimate with fork trail, wheelbase and BB height ........

Lovely sport.

 

[Frankenorange]

Fit wise I just went with the same setup I would have on a road or CX bike as it is for road and byways not singletrack, or rock gardens.

Have a look at http://yojimg.net/bike/web_tools and play with the trail/flop calc and the stem calc. I found these really useful for selecting stuff. There are also a bunch of trail figures for various CX bikes there too. My selection of fork lowered the BB but by so little it isn't noticable.
With 80+ kilos at 4 foot higher above the BB an inch or two wouldn't be noticed. Maybe striking roots/rocks is a problem for some people, with low BB's, but surely it would have to be super low road spec and long cranks to be an issue. I dunno. There is always going to be something that nature has put in the way that will argue with part of the machine, or the rider!

Bar wise i use some old school road champions with the randonneur bend. Nice and narrow on the hoods for the road and a tad wider in the drops for off-road, and i haven't died yet being on the hoods offroad. I started the build with 46cm bars as i wanted to try wider, but quickly went back to the narrow road champions. I also had a try of some modern compact bars(soma Highway One) to test the compact shape. They were 42cm., but i couldn't get on with the bend. It was reet odd to hold and almost like it wasn't there to hold which sounds nuts. Anyway....i am back on the old school bars. They are plentiful and cheap.
Lets be honest about bar width.....Paris-Roubaix is mental and they manage just fine without ridiculous wide bars, like the Towel Rack and bars Ronald Romulan promotes, for instagram likes. If narrow suits then use narrow.

At the end of the day a bike is just a couple of triangles(in most cases) with some hoops at each end and bits to hold on to, and sit on. It just has to fit well and not wobble about, rattle your teeth out, or scare you.

Edit to add..... i forgot to say that a Thomson layback post can be used in reverse(it is or was in the Thomson FAQs) to effectively steepen the seattube and get your knees where you want them. Depends on frame and your skeletal geo, of course. Alot of people hate the look, but it isn't their bike so just put them on ignore if you need to use one. Forwards, or backwards.

 

[Tsundere]

After reading through this thread I've decided to do something very similar with an aluminium frame. Still doing the steel dirt drop build but that's for another thread and another time.

I found a cheap ally frame that seems to come the close to Cunninghams design, at least in terms of geometry if nothing else..

Anyway not trying to hijack your thread, It'll get its own thread once the project is fully underway, I'm just wondering what you are planning to do about forks? Are there any similar forks out there that would match those on the Cunningham?

Keen to see how your build progresses and hoping to pick up some valuable tips and pointers on the way.

 

[doctor-bond]

So, cheapo 450mm post has arrived and I’ve done a bit of measuring .... as you say Franken, at the end of the day just a couple of triangles (great link BTW); and it looks like I can get the same bar to saddle nose distance as my tourer, along with level bar/saddle height. And, the arse to rear axle distance will be within a few mm. I may even get away with a 410mm Thomson for aesthetics.

I find this from Bikeradar a sensible and comprehensive guide to geometry BTW.

The fly in the ointment is coming from the fact that the Cannondale frame I’ve found is the beast of the east geometry: a high 33cm BB height along with long wheelbase (longer than my Randonneur).



That means the bars will have to come a bit higher to reach the saddle level, and the LD stem I have may be a bit low. I could use a very tall dirtdrop quill - getting very gangly though ......

Hmmm. The proof will be in the riding, so I think it’s time to build it up and have a go. I may have to get another donor frame, and am thinking normal geo Cannondale, either 3.0, 2.8 or Cad3 (maybe even Killer V which takes it away from the Cunningham but would be great to startle other road users!)

But the way that Hardrock lines up is uncanny! just goes to show how ahead of his time CC was. How much does it weigh Tsun? Can’t think of many Aluminium frames with a chainstay Ubrake - Fisher CR7? In terms of forks, I was planning to go with Pepperoni which are light and have a bit of curve. The Potts fork on the inspiration bike is curved, but I think Jacquie rocked a straight fork, so maybe a project 2 would work? (You could mask up a curve shape to give the impression of the Potts sleeve?)

 

[pw_pw_la]

Loving this!

Reading/following along with interest now, as I want to do something similar in the next year.

You too @Tsundere! Post up where you're at with it once you have that frame in hand.

Some really good intel and opinion in this thread already.

Can we start a club for people too poor to ever get a Cunningham? Only membership requirement is building a bootleg version on the cheap!

To be honest, @Radrider's steel dirt drop Bonty project really wet my whistle. Especially in thinking about building something along the lines of what you're all discussing:

https://www.retrobike.co.uk/threads...drop-syncros-salsa-chris-king-goretex.437302/
That's close to perfection in my eyes.

Other than the two very traditional MTB builds I have in the dock for 2022, starting a dirt drop/CX build is high on the priority list. As is a comfy, cruisey, parts bin special camping ride!

I want to get weird.

 

[legrandefromage]

Heres another I made earlier - forgot about this!

 

[legrandefromage]

Heres another - I get that its not 'just sticking drop bars on an MTB' thread, its creating something that is just a little versatile, different and something that fits (hence the bigger and biggerer frames!)

Personally I cant get on with dirt drop bars and prefer wide road bars. Sometimes the 'ATB' frame is as good as a road bike and gives as fast a feel off road with all the advantages of multi hand positions on the drops. Then theres the bar end shifting, my personal favourite over anything else as they are so versatile to a tight-arse like me who doesnt want to spend money on compatible mechs...

The Yellow Peril

 

[doctor-bond]

Yes, the challenge here is not just to do a dirt drop conversion, but to do one that is fast (light) enough, and comfy (fits) enough to do 150 miles in a day over big hills. For me, the golden comfy rule is that the top of the bars need to be at least level with the saddle, not below. That’s why the inspiration is a Cunningham not Tomac. I’m convinced that many people don’t enjoy their dirt drops because the bars are too low.

My attempts to date have hit the comfy/fit target and are good for touring, but both would be too heavy for 150 in a day. Bigger frames allow the front up, but not for free.

The much-missed ’Dale below was fine on a York-to-Filey-and-back-with-fish-and-chips type ride, but just too chunky for the Coast to Coast.




And for proper multi-day camping trips, weight isn’t the biggest issue, so good steel and a decent position win out:





All of which means I’m going to go Aluminium and small frame, with the challenge of making it fit. (Hair shirt? What hair shirt?)

 

[legrandefromage]

Yes, everything I build seems to end up looking like this...

 

[hamster]

For me, the golden comfy rule is that the top of the bars need to be at least level with the saddle, not below. That’s why the inspiration is a Cunningham not Tomac. I’m convinced that many people don’t enjoy their dirt drops because the bars are too low.

Wise words. Drops need to be comfortable and usable - anything else is just fashion. Most road riders (non-racing) also have drops too low in my view. What suits a 20-something Pro who rides 50,000km per year (and who is paid to be in pain) is not right for the rest of us.