Wheels Of Steel

I got to thinking: Why would one want a touring bike built out of higher grade materials, especially if it's going to be well used and abused. Reynolds 853 tubing is lighter and thinner than 631, correct? Weight is a consideration, yes, but I'm sure a 631 frameset is light enough.

robow

You might consider posing this question in the "frame builders" forum as they can discuss ad nauseam the attributes of each of those steels and which might be more appropriate for your needs.

fietsbob

tell about the wall thicknesses and the outside diameters of the frame tubes

853 and 631 and 531 are product designations of the tube set Maker ,

doesn't give that much more information.

a super high strength alloy and heat treatment process can be used to allow the tube walls to Be thinner.

but that is not like real data.. How much thinner? IDK, DO you?

too light and it wont handle the weight carried (unless you just ride with Money)

tarwheel 

My Bob Jackson World Tour is made from Reynolds 631, but it is a special tubeset designed for touring bikes. It has thicker walls and perhaps butting than regular 631. I'm not sure if regular 631 would have any advantages over any other tubing. I have another bike (Gunnar Crosshairs) made from Reynolds 853. It feels lighter than the BJ, but I haven't actually weighed the two bikes set up comparably. I haven't ridden the Gunnar on a tour so I don't know how it would handle fully loaded, but I use it for commuting and have carried moderate loads plenty of times. The Bob Jackson is definitely a stiffer riding frame unloaded, and for that reason (in part), I run 32 mm tires on it. The frame is a little too stiff for my preferences riding unloaded on 28 mm or narrower tires. The Gunnar, in contrast, rides very nice on 25-28 mm tires.

fietsbob

My Japan sourced steel 86 Specialized Expedition had a 1.125" top tube, and a 1.25" down tube .
and it still flexed with every pedal stroke , on tour, with 4 panniers .

Liked my heavier bike better ..


thought an 1x2" Oval tube would be a benefit .. horizontal on top, vertical; for the downtube..

grolby

Because nice things are nice. Not that 631 isn't nice, but I think you know what I mean. Some people take pleasure in having high-end things, for the sole reason that they are nice and high-end.

Heck, at this point, I think you could legitimately make a fantastic loaded touring bike out of carbon fiber. There's not really a market for it, but a stiff and durable CF touring bike is certainly doable - And that would be nice. Is there much reason to do it? Well, no. There's not really a market for it, either. But heck, if you went to Calfee and asked for one, I bet they would at least consider building it.

LeeG

Nothing wrong having a touring frame made out of costlier materials as long as the design utilizes the materials appropriately. No sense in having a touring bike made with costlier materials that are dimensioned for light duty use. A truck doesn't have to be made out of titanium and carbon fiber to haul junk.

Wheels Of Steel

Any framebuilders care to weigh in since having this thread moved? Your expertise and insight would be greatly appreciated.

Scooper

Personally, for a touring bike I'd use 631 because the slightly thicker walls would be a little more dent resistant. The chemical composition of 853 and 631 is identical, but 853 is heat treated. The heat treatment makes 853 stronger, so it can be drawn thinner. The thinner walls will make 853 more prone to dents.

Here's how 853 and 631 compare, both in chemistry and strength. 631 has about 2/3 the ultimate tensile strength of 853, but it's still plenty strong enough.



Reynolds 631 Range


Reynolds 853 Range

DaHaMac

Not a framebuilder but a steel lover.

My touring bike is a Raleigh Sojourn in R-631. I commute on this bike mainly and unloaded it is stiff but still smoother than my aluminium framed bike. My Brevet bike is a Raleigh Clubman in R-520. The tubes are smaller in diameter on the Clubman and the ride is smooth.

Reynolds offers a material breakdown on their site:
https://reynoldstechnology.biz/our_materials_631.php
https://reynoldstechnology.biz/our_materials_853.php
https://reynoldstechnology.biz/our_materials_520.php

LuckySailor

So, I'm still puzzled. R-520 and 725 are the same metal. Both well respected, one at the low end the other at the high end. So what is the big deal if your tubes have been heat treated? Is it just more dent resistant? And If you can get a 520 frame for $400 is it really worth 3 times to get 725?

Andrew R Stewart 

As has been said before, A "stronger" (say, heat treated) tube will allow less metal be present (thinner walls0 and still be strong enough for the job that a frames has. This more costly tubing will, however, be more flexible. If it has the same tube diametersm and is steel then the thinner walls will be less stiff by a small amount.

However the more costly tubes (of thinner walls and being heat treated) are often used in a larger diameter, the thinner walls help offset the added weight of the larger diameters. So then the frame is strong enough, stiffer and no heavier then the lower cost one.

The more costly tubes (thinner walls) do require more care during the building as they are more easily dented and have less wall to withstand under cutting filing or weld beads edges. So the greater cost of the heat treaded tubed frames comes from the extra and more skillful labor as well as the higher material cost. Then there's the marketing value increase, but that's another topic.

So a touring/travel bike that needs to be stiff, strong, dent resistant, possibly field repairable (think third world tours, there's lots of cool unpaved paths out there) all make the more basic/thicker walled tubes a good choice. The slight weight difference between the thinner walled tubes and the thicker walled ones is less then 1% of a fully loaded bike's weight. Not too much, I think we all can agree on.

Now where I do think the nicer stuff is very justified is in the components and gear. Andy.

Scooper

Both ultimate tensile strength and yield strength are greater with the heat treated 725. This means that 725 can be drawn with thinner walls and therefore will be lighter.

The downside is that thinner walls mean the frame won't be as stiff (given the same diameter tubes) and the tubing will not be as dent resistant.

LuckySailor

Thanks Andy. I appreciate the info, and ultimately, support to my argument-more expensive doesn't mean it's necessarily better. I went with a 520 when I easily could have gone with waay more expensive. Glad I made the choice I did.