Designing a touring frame/fork
 

I'm sure this has been hashed over extensively so I apologize if this is getting redundant. However, the discussion always seems to bring out great information and a variety of opinions to consider.

I have the opportunity to design a touring frame from the ground up. I've been on a couple of extensive tours with a nice old Trek on 27's so I have some ideas about what I like but I'm always interested in what folks could have or want if they could design their own frame.

Let's also not limit this discussion to frame/fork. If you want to input information about components, handlebars, racks that's fine with me too!

There`s a lot of opinion involved about wheel size, frame material, geometry, and threaded/threadless. One little detail that doesn`t get mentioned and I think would be nice is oversized rack bosses for 6mm screws, at least for the lower rear mounts. Or if you`re a trailer minded person, maybe brazed on BOB studs. Or even both of those so you can do it however you want.

Reynolds 853 Oversize tubing (31.8 TT and ST; 34.9 DT); 1 1/8 headset (Chris King), Unicrown Forks; Thompson stem and seatpost (29.4mm) ; 73mm BB (XT Cranks M770)22 32 44 ;
26 inch wheels, Hope Hubs, Mavic EX 729 Rims 36H, 9 sp 11-34 cassette; Paul Thumbies with Dura Ace Bar End shifters; XT F&R der; Magura HS33 Brakes, Flat Bars; Tubus F(Tara) and R(Tubus) racks.

Are those going to fit on a standard rack?

Close. I imagine most mfgs drill (or even punch) the holes around 5.5mm. Reaming them out to an even 6 would only reduce the meat by half that difference all the way around. But if I were already that far into custom territory I wouldn`t stop at the frameset anyway- may as well have a dream rack on my dream bike.

Jeepers, how did this happen? Tell us!

Before this thread runs away, it would be good to tell us a few more parameters: on road, or off touring? Within civilised areas, or the third world? What's the budget? Is this one off, boutique, or mass market?

Bear in mind there are already gazillions of touring frames on the market, you could average them all out to see what people need :) Five hundred braze-ons would be a good start.

Sakkit bicycles came were offered with the option for a security 'plug' built into the seattube, a waterproof sealed compartment accessible from a fitting in the seattube between the derailleur and the bottom bracket.

IF I were designing a custom touring bike from the ground up for my specs, I would get the fitting for this - have seen it at framebuilder sites that offer lugs, etc... and ask it be installed in your frameset. I suspect you could have it installed right at the derailleur clamp area so it would blend right in.

you never know when you're going to need to smuggle some diamonds across a boarder ;)

An integrated rear rack with 15 inch deck might be nice.

decks and fittings for water cans of some large sort if you are travelling third world as well. a simple inverted T configuration with 3" angle rail at the bottom with a strut leading to a strapover to secure an edged water container on the rail of the T would be sufficient.

Water carrying on the front fork is nice. maybe integrate a watercan hauling system with a lowrider rack, integrated and welded to the fork.

I believe there was a fairly well known, record setting, knighted British cyclotourist that used integrated jerrycans or something like this, he recently passed, RIP, and I've forgotten his name, it escapes me.

Rodriguez puts a bottle opener on their touring frames but it strikes me as more of a conversation piece than something that would be useful (assuming one would be carrying something like that already).

The Tout Terrain bikes that Peter White Cycles sells seem to be the ultimate fantasy tourer bikes.

One of the custom tandems in Touring Bikes: a Practical Guide has a fuel container built into the downtube with small screw stoppers each end. Im not sure if this would prohibit the bike from air travel.

The fuel bottle thing makes me think of a bike I saw on a link from the Sands Machine (S&S couplers) website- some guy found a way to stash a fly rod inside his coupled frame.

Google "Tony Oliver" for an informed view of what proper touring frame should be.

I found that bicycle last week. I love the idea of an integral rear rack.
It weighs a bit over 32 pounds as pictured. It has fenders, a generator & light, and a Rohloff hub and disc brakes, each of which will make the bicycle a bit heavier. Does 32 pounds sound like a lot? I really don't know. I own two bicycles and have never weighed either of them.

32 lb isn't light, but light weight obviously was not a design priority. Considering that's the "all-in" weight, it doesn't sound bad. I'd be more concerned with how much lighter my wallet would be.

Top-end racing bikes these days weigh as little as 16 lb. My own racing bike weighs about 21 lb (it's about 10 years old, and I did not choose especially light parts for it). If you added fenders, lights, a rack, and a dyno hub to it, it would top 25 lb. And it would make a lousy touring bike.

It`s a touring bike. 32# is pretty light for that- a lot less than I would have expected for that bike and about the same weight as mine. Sheesh! My roadie runs about 25 with empty bottle cages!

Well, if I were really going to redesign a touring bike from first principles, I'd start by assuming 20" (ISO 406) wheels. A wide variety of tires is available, they're big enough to allow sufficient mechanical trail that you can have stable handling. 20" is big enough to be efficient on rough surfaces. The smaller wheel will allow a lower center of gravity and will open up all kinds of frame / luggage options.

some kind of electrical system built into the bike that would charge up whatever need's charging,might sound daft but how many times have you looked for somewhere to charg you phone /lights/batterys,also keep the frame as light and as strong as you possible can.it will be near on impossible i think to improve on the top touring bikes, imho the only way to improve things is add on's, but what they are i have no idea.oh yeah a kickstand that works.love to know how you get on with this project hope it works out.

RHM: Something like this perhaps?

I think the frame is relatively simple. If you have toured and are of technical mind set, moderately, then you should have a good idea on fit, and you should have enough experience with various tubes to know what range you get solid performance out of. I think the main thing beyond that is to accept that you are going to have to build a couple of frames to get it right where you want it. It's a bit like marriage. If you are lucky the first marriage may be perfect. But if not people tend to rebound, decide the one feature they need to go overboard on is the one missing in their initial go around. It can take two shots to get it right. I have been down that path so many times with various projects. Though not marriage...

I am not a big believer in the integrated rack. I don't see the point. If the idea is that one needs to have a stronger attachment point, there is no reason why that has to be done at the cost of reducing the versatility and options for a rack. The same line of thinking would suggest that the drops should be welded to the axles. There isn't anything wrong with properly sized bolts. But the attachment points should be larger. the current eyelets were really designed for fenders. I haven't really seen a successful integration of the rack in a way that allows the rear end and the rack to be made more efficiently, so they share common parts, save weight. On a rear suspension rack, I think there are some better options.

One thing that does work really well/differently, is to integrate the rack into the panniers. Solid shell panniers that do not require a rack are very light and potentially far more aero. I made a set out of 1/8 inch ply and glass for my mother's city bike 10-15 years ago, and they were really useful and light. The problems are that you are stuck without a rack; they don't ship well; They don't deform to accept that little extra piece of gear; you can't detach the bags; etc... But for just riding with they are excellent, which is why they are so popular on motorcycles, at least the hard shell part. Many of these problems can be worked with, but every rider will have their own features list so best of luck to the commercial maker.

I really think they got it right back in the '90s with the hardtail mountain bike frames. I would use those angles combined with a long headtube to get your handlebars high enough for a modern threadless headset. You could use this setup with 26" or 700c wheels depending on your size and preference.

Enjoy creating the bike of your dreams:thumb:

A welded joint can transmit torque through the joint; a screw connection cannot transmit any torque. Hence, an integrated rack can handle lateral loads such as the bags wagging left to right. The tubing can be downsized because the loop over the rear wheel does not have to be as strong.

This torque is akin to how motorists put load-adjusting bars on a trailer hitch to transmit torque to the frame of the towing vehicle. It is the same torque that S&S Couplers are designed to transmit torque through the top tube and downtube of a bicycle.

"A welded joint can transmit torque through the joint; a screw connection cannot transmit any torque. Hence, an integrated rack can handle lateral loads such as the bags wagging left to right."

I'm no engineer, but I don't see that bolt on racks of proper construction have any problem resisting bags wagging left to right.

"The tubing can be downsized because the loop over the rear wheel does not have to be as strong."

But this is not what I have observed on the touring type bikes that attempt this:

http://www.bikebrothers.co.uk/ianhib...1_files/06.jpg

http://www.peterwhitecycles.com/tout-terrain.asp

As far as improving rack attachment is concerned there are many tested ways that go beyond the current fasteners without the lack of flexibilty of welding/brazing a rack on. Not all of these use bolts in the conventional maner, they may support the weight of the rack directly with the bolt merely securing a ferule etc... I still think that the most practical approach is to use upgraded bolts and fittings since this nips the problem in the bud, but if there is some disaster a resupply rack can be quickly fitted.

Mine would be close to that Tout-Terrain Silkroad, but add an integrated, suspended high-rider front rack with shelf. Add a Schmidt dynohub for that fork (doesn't exist yet) and The Plug. I think a rear fender could be part of the frame as well. The frame should accomodate a Topeak Modula XL cage for 1.5L bottles and a standard bottle cage.

You're thinking of Ian Hibell, who did unfortunately pass away recently. He had a couple bikes made with integrated (not removable) racks because he apparently had trouble with racks and rack bolts breaking. I've only ever seen his jerry-cans strapped to the bike, not in special holders, though. see below. I love the old school "folding tire."

http://www.bikebrothers.co.uk/ianhib...s/camack_r.jpg

This guy has lowriders with water containers: http://www.bicycletraveller.de/equip.htm

Scroll down the page for details.

Peter, the third sentence of the Silkroad link you provided says: "The rack itself is stronger, stiffer and lighter". Further down it says: " The maximum carrying capacity of the Silkroad is 350 pounds." Any off the shelf rack that can carry what that rack carries is going to have a lot of parts and still give the rider the risk of fastener failure. http://www.blackburndesign.com/racks.html#ex_1

Your solution with sockets could transmit the torque a bit better. There is no rack to mate with it, though. Won't help you fifty miles outside of Peoria.

Nice idea on the cage. Since you are a fan of the Silkroad, do you think I could put a long-reach caliper brake on the rear brake bridge? I am not sold on the disk brakes. By my reckoning, disk brake parts add 200g to the weight of a Kona Project 2 fork.

"Peter, the third sentence of the Silkroad link you provided says: "The rack itself is stronger, stiffer and lighter"."

I'm sure they do say that, stronger stiffer and lighter than what? The majority of racks out there are not stronger than chromo racks by any number of better makers. So anyone with a chromo rack can correctly claim that. Lighter I don't particularly believe based on the number/size of tubes. It is a fairly normal shape rack and would attach just as easily with screws if it were not welded. Of course welding is lighter than screws and fittings, just not by any substantial amount.

Do welds make it particularly rugged. I see no reason why that would be so. Welding has a number of disadvantages like deflections that need to be cold set out, and weakening tubing. Of course all racks are welded or brazed so it isn't a big deal, except that with this rack you put all your eggs in one basket. If it falls appart, or more likely is damaged in use, it isn't as easily swaped out. We could take the view that everything that is attatched to the bike should be welded on: brake levers handlebars, derailleurs. But we prefer the wider selection, versatility and easier replacement of parts that are bolted on, and can come from various manufacturers.

Since I am making both my racks and my frame, nothing would be easier than welding the rack to the frame for me. I can see the appeal to manufacturers, it is cheaper to do, they get the rack sale, and they get some value from selling it as an improved design. Next I suppose we will see some S&S couplers for welded racks so the darn thing can be removed and packed. :)

"The maximum carrying capacity of the Silkroad is 350 pounds." Any off the shelf rack that can carry what that rack carries is going to have a lot of parts and still give the rider the risk of fastener failure."

We are talking rider, bike weight, and gear not rack capacity I assume. My cheapo touring bike carried that without a groan, mostly my weight, and the blackburns did the rest. Blackburns are fine for most people's expeditions, they do become disasters over the long long haul. But many trans Canadas get done with the aluminum clones. 7000km being a long ride but a short service life. next time one goes on a 7000km ride on just buys another 15 dollar rack.

There is a risk of fastener failure to the same extent there is a risk of weld failure: It approached zero when parts are properly sized and competently assembled. The problem is we are mostly stuck with the 5mm system which is not keeping up with advances in technology, and advances in the kinds of trips many people now take. The fix is as simple as moving to 6mm. The problem is entirely a marketing thing. Would I prefer a Silk road frame to an identical one with 5mm bolts? Probably. The manufacturer is getting a lot of buzz out of the welded on rack. The problem for someone doing the sensible thing and moving to 6mm is people will probably avoid them on the grounds that "they are the makers of that frame nobody's racks fit". While the welded on rack make the TT cool, otherwise it looks pretty much like any other mountain bike.

I would prefer the new BG frame with US make chromo BG racks to the TT, asuming all else is equal I would probably go that route particularly if they had a 6mm option. I think someone like Surly ought to bust a move and offer 6mm fititngs on their expedition (26") LHT. They sell racks that have removeable bits that could be substituted in 6mm, possibly their rear rack could be drilled out.

I don't really care if an integrated rack is theoratically better or not. All things equals, it just looks better. One thing is certain, welds don't unscrew themselves from vibrations.

I have no idea. I'm just that, a fan. :D I like the principles behind the Silkroad but it's way out of my price range.

The thing about the bottle cage is
1) these Topeak cage are great for touring. A single 1.5L bottle has as much water as two typical 750ml bike bottle.
2) I have a bike which has the cage braze-ons too close to fit even one large bottle cage. Fitting two can be difficult on bikes with sloping top tube (not enough room on the seat tube) but if designed a bike, I'd make sure I can fit at least one.

If you want to believe that a 5mm screw and bolt is as strong of an attachment as the tube welded to the rear dropout of the Silkroad, then go ahead.

BTW, I am an engineer.