Author Topic: Tyres for DT Swiss XR425 rims  (Read 489 times)

schw

  • Newbie
  • *
  • Posts: 5
Tyres for DT Swiss XR425 rims
« on: August 18, 2020, 07:26:08 PM »
Hello everyone

Thanks to another user of this forum I’m now the very happy owner of a lightweight Raven.
Rims are DT Swiss XR425: internal width 17 mm, rated for tyre widths 38 mm - 57 mm.
Min 38 mm seems very wide, and I have a set of Schwalbe Kojaks in 35 mm (folding) I was hoping to fit. Would this be a bad idea? Would they be likely to fail in some way if I could get them seated and kept them at a moderate pressure?
If the Kojaks are no good I will probably get some 42 mm Paselas, unless anyone has any other recommendations. Hoping some of the newer gravel tyres might trickle down to 26" soon..

Thanks for your thoughts!

Pavel

  • Full Member
  • ***
  • Posts: 107
Re: Tyres for DT Swiss XR425 rims
« Reply #1 on: August 18, 2020, 08:18:17 PM »
I'd be interested in a review or your thoughts on the rim and tire combo, especially how you like the rim after some mileage.

I'm sort of surprised that a 17 mm rim would be rated for such wide tires. I'd think rims with 22mm ID or more even, would suit tires such as 50+.

I have Velocity Dyads in 700mm with 37mm tires, and that seems just about right, though I wouldn't. be likely to put tires much wider on the rims.  They have 18.6mm at the inside and Velocity states, in their literature that tires between 25mm and 38mm are optimal.

Andre Jute

  • Hero Member
  • *****
  • Posts: 3474
Re: Tyres for DT Swiss XR425 rims
« Reply #2 on: August 19, 2020, 05:53:23 AM »
The ERTRO rule was and probably still is (formally if apparently universally disregarded) that the minimum width of the rim across the bead retainers should be no less than 40pc of the tyre width. But when the 29er craze started, there were very few balloon tyres available and no one knew whether the craze would last. The rim manufacturers whined that it would cut into their profits to make wide rims for tyres that may not sell. The tyre makers in their turn whined that if the rule stood and there were no rims, it would cut into their profits to make illegal, unsaleable tyres. Since ERTRO is the trade body in Europe of the tyre and rim manufacturers, an EU-driven transnational cartel which makes its own rules with zero political supervision, it was suddenly discovered that in the case of wide tyres the 40pc width rule could be broken with impunity because the EU had decreed that the tyres dare not part from the rim, or split rims perfectly adequate for narrower tyres down the middle... This decision undermined the entire scientific relationship between tyres and rims. (1) It didn't take long for bicycle rim makers to bring their own pneumatic jack hammers to widen this loophole into a whole new one-size-rim-fits-all-tyre-widths marketing religion.

Serious cyclists would be well advised to stick to the proven and tested ERTRO rule before that body put profit above the safety of cyclists, and fit the widest rims they can find. Note that the now disregarded 40pc rule was a minimum. You should in fact fit the widest rims you can find that takes a tyre that your fork has space for. The reason is that the wider the rim, the lower you can pressurise the tube without dire side-effects. Conversely, the narrower the rim and the wider the tyre, the higher you must inflate the tyre to keep it on the rim, in the process courting a life-threatening disaster of a rim being split by the tube pressure. In effect, if you buy narrow rims, you're wasting your money on fat tyres because you will have to inflate them to a pressure where they will ride harshly and give you none of the benefit you paid for.

Unfortunately, it isn't so easy to find wide rims. I'm lucky to have 24mm wide rims which let me run 60mm wide Big Apples at relatively low pressures (at the end of the month, when I reinflate, sometimes down to 1.5 bar), but those are from 2006 and replacement is likely to be a problem. But a good place to look if none of your favourite bike vendors make suitable rims is mountain-unicycles, called muni, which ride on rims up to 38mm wide.

Good luck finding suitably wide rims for your preferred tyres. Stay safe.

(1) An example of similar lawmaker unlawfulness currently in the news is forcing people to wear masks and keep a socially responsible distance to curb the spread of the Chinese virus -- except for those who are "peacefully" rioting, looting, burning and assaulting citizens, who are politically deemed to be incapable of spreading the disease. Once more, ERTRO is a European Union body, the European Tyre and Rim Technical Organisation (ETRTO) which exists to specify and harmonise sizes of rims and their associated pneumatic tyres across the European Union -- except when its purpose suddenly becomes the profit protection of rim and tyre manufacturers, and damn the customers.

martinf

  • Hero Member
  • *****
  • Posts: 727
Re: Tyres for DT Swiss XR425 rims
« Reply #3 on: August 19, 2020, 08:57:31 AM »
I currently run Kojak 35 mm width tyres on my Raven Sport Tour with Mavic 717 rims, which have the same internal width as the DT Swiss XR425.

No problems.

I have also tried narrower 28 mm width tyres on these rims. They work perfectly well, but the ride is of course harsher.

In the past I have used Marathon Supreme in 50 mm on the same rims, but on another bike. 50 mm is OK on these rims, but like André I think they work better with a wider rim.

I currently have 50 mm Supremes on 5 family bikes and 42 mm Supremes on one bike, with internal rim widths going from 19 mm to about 22 mm. IMO even wider would be better for the 50 mm tyres, at least something like the Andra 40 at 25 mm, but good quality wide rims for rim brakes are not easy to find in 26" size.

As they have performed well on other bikes I will probably fit Schwalbe Marathon Supreme in 42 mm width on my Raven Sport Tour when the Kojaks are worn out. I haven't got mudguard clearance for 50 mm tyres on this bike so 42 mm is about the maximum.

I don't think Kojaks are as bad as the site below says, so I take their results with a pinch of salt. Their tests give 24.8W as the rolling resistance of Kojaks at 60PSI, whereas it is 23.6W for Supremes at 45PSI. 42 mm Supremes are wider than 35 mm Kojaks so I would run them at a lower pressure :

https://www.bicyclerollingresistance.com/

So I reckon going from 35 mm Kojaks to 42 mm Supremes will have the advantage of more comfort, better durability, probably better puncture resistance and not much effect (if any) on performance.

In my experience, Supremes roll well, don't seem to puncture very often, will cope with mild off-road use and last for a long time. The sidewalls are thin and supple, so fragile compared to some tyres. So far this hasn't been a problem for me. The similar but tougher Dureme sold by Thorn is slightly heavier and slightly slower on smooth tarmac, but probably a better choice if doing a lot of off-road riding, AFAIK Dureme is only available in 50 mm.

PH

  • Hero Member
  • *****
  • Posts: 985
Re: Tyres for DT Swiss XR425 rims
« Reply #4 on: August 19, 2020, 11:17:39 AM »
Are these tubless ready rims?  If so some of the conventional wisdom about normal clinchers may not apply.
Normal 17mm internal rims are good for much narrower, for example the Exal LX17 are advertised as suitable for 25 - 50, though I'd suggest 30 - 40 was where they work best.

schw

  • Newbie
  • *
  • Posts: 5
Re: Tyres for DT Swiss XR425 rims
« Reply #5 on: August 21, 2020, 11:36:12 PM »
Pavel,
I'm surprised at the rating, too. So far they feel very light and quick, especially from a stop. I'd be extremely surprised if I could push them to a point where I had any concerns about rigidity or durability. That said, I don't have much to compare them against. What's your experience been with the Dyads?

Andre,
Noted, but I'm considering fitting tyres narrower than recommended to older 26" rims.
I've generally assumed (and never had reason to confirm) that *maximum* rim width would be an external width equal to the tyre width; is there a rule for this?

Martinf,
That's good to know about your Mavics. I see their manufacturer recommended range is 25-52 mm, which seems to make sense.
The bike came to me with Duremes which I am finding very sluggish. I'll have to see how acceptable I find the comfort level of the Kojaks vs how much I enjoy the quietness, aerodynamic advantage, lower BB height, and lower standover! If I find them lacking, Supremes will definitely be on the shortlist. How much of a difference do you notice between the 42 mm and the 50 mm?

PH,
That's a good point about tubeless ready, thanks. Not the case for these rims though. I've attached an image of the cross-section which looks conventional as well.

schw

  • Newbie
  • *
  • Posts: 5
Re: Tyres for DT Swiss XR425 rims
« Reply #6 on: August 21, 2020, 11:37:17 PM »
Thanks everyone for your input.

It sounds like there's no obvious reason why the manufacturer should recommend such wide tyres. This was designed as a XC racing rim, so maybe they assumed that 1.5" would be the minimum tyre that users would be looking to fit.

And perhaps I should have said, this is a small Raven with narrower tubing and the 853 fork, which I'll mostly be riding minimally loaded on pavement. I'm a light rider and this will be my fast(er) bike.

So I'll go ahead with the Kojaks and see how we get on.. My other Thorn is an offroad cruiser/utility bike with sensible balloon tyres ;)

Andre Jute

  • Hero Member
  • *****
  • Posts: 3474
Re: Tyres for DT Swiss XR425 rims
« Reply #7 on: August 22, 2020, 03:29:57 AM »
Andre,
Noted, but I'm considering fitting tyres narrower than recommended to older 26" rims.
I've generally assumed (and never had reason to confirm) that *maximum* rim width would be an external width equal to the tyre width; is there a rule for this?

I'm not at all sure a 1:1 rim to tyre width ratio would make sense, but in any event the only tyres for which it would in real life be a consideration would be sub-20mm racing tyres for which there are wider rims available than tyre width. Whether the rim is too narrow or too wide for the tyre, the solution is greater pressure to lock the wire bead into the retainer.

I don't even want to contemplate the fact that the most popular of the real balloons, the Big Apple, these days is actually a folding tyre without a wire bead, a design that until a few years ago even in the Big Apple was an extra-cost option and sold as a weight-saver model called "Leicht". It seems to me likely that eventually, with the success of the Big Apple in use and sales, that design will reach the touring designs, if it hasn't already (I haven't checked but you should -- the Kojak is, IIRC, a part of the Big Apple family of balloons).

For any tyre a modern tourer will want to ride on, the problems isn't that rims too wide for the tyres rain like manna from heaven but the exact opposite, the shortage of rims that are even minimally wide enough.

As an example, it is known that mountain unicycle rims 38mm across the beads work superbly well with 60mm Big Apples, allowing a 350lbs bike mechanic to ride the combo at an inflation pressure of only two bar, say 30psi, without fishbites or other problems. 38mm rims successfully applied to 60mm balloons -- ratio 63.3pc -- under a rider of 350lbs has led some of us to conclude that the rim width to tyre width ratio should be between two-fifths and two-thirds, say up to 67%.

Ratios outside that will work under most normal circumstances but this sort of rule is made for the exceptional but foreseeable circumstance, if foreseeable is defined as "unexpected face plant". A touring bike is after all an adventure bike.
« Last Edit: August 23, 2020, 01:48:16 AM by Andre Jute »

martinf

  • Hero Member
  • *****
  • Posts: 727
Re: Tyres for DT Swiss XR425 rims
« Reply #8 on: August 22, 2020, 08:06:56 AM »
Martinf,
That's good to know about your Mavics. I see their manufacturer recommended range is 25-52 mm, which seems to make sense.
The bike came to me with Duremes which I am finding very sluggish. I'll have to see how acceptable I find the comfort level of the Kojaks vs how much I enjoy the quietness, aerodynamic advantage, lower BB height, and lower standover! If I find them lacking, Supremes will definitely be on the shortlist. How much of a difference do you notice between the 42 mm and the 50 mm?

I've ridden 5 tyres (that are still available) that you could fit on 26 " rims on a Raven. My (subjective) ratings for these are (1 is best and 5 is worst) :

Rolling resistance :
1 Continental Grand Prix 28x559 folding
2 = Kojak 35x559 folding
2 = Marathon Supreme 42 x 559 folding (I actually rode the 42 x 584 version, but assume that to be pretty much the same, see next line)
4 Marathon Supreme 50 x 559 folding (I currently have both 50 x 559 and 50 x 584, and can't tell the difference)
5 Marathon Dureme 50 x 559 folding

Comfort :
1 Marathon Supreme 50 x 559 folding
2 = Marathon Supreme 42 x 559 folding
2 = Marathon Dureme 50 x 559 folding
4 Kojak 35x559 folding
5 Continental Grand Prix 28x559 folding

Durability (also applies for puncture resistance) :
1 Marathon Dureme 50 x 559 folding
2 Marathon Supreme 50 x 559 folding
3 = Marathon Supreme 42 x 559 folding
3 = Continental Grand Prix 28x559 folding
5 Kojak 35x559 folding

Off-road performance :
1 Marathon Dureme 50 x 559 folding
2 Marathon Supreme 50 x 559 folding
3 Marathon Supreme 42 x 559 folding
I don't consider the Kojak 35x559 or the Continental Grand Prix 28x559 suitable for off-road use.

Price (cheapest first) :
1 Continental Grand Prix 28x559 folding
2 Kojak 35x559 folding
3 Marathon Supreme 42 x 559 folding
4 Marathon Supreme 50 x 559 folding
5 Marathon Dureme 50 x 559 folding

Your other criteria :

- quietness.  Not something that bothers me much. In the list of 5 tyres, the only one that I noticed that made a (slight) noise was the Dureme.
- aerodynamic advantage. Not noticed any difference in the 28 to 42 size range, but see below.
- lower BB height, and lower standover. Finally something that isn't subjective. For lowest height, same as "Price".

Another thing to consider is the true size of the tyres, which depends to some extent on the rim width and inflation pressure.
The 28mm Continentals are really 28 mm, all the other tyres are slightly smaller than their rated size. In the sizes you are considering, I measured the Kojaks at 33 mm and the Marathon Supreme 42 x 559 at 37 mm, so less difference than you would expect from the stated size.

Yet another thing to consider if comfort is important is that, for a given size, tubeless should be more comfortable than using a butyl inner tube. On some bikes I use latex inner tubes, which are IMO in between tubeless and butyl as far as comfort and hassle are concerned. I do notice the difference in comfort between butyl and latex, and with some tyres I also notice an improvement in rolling resistance.

And if you want the lowest rolling resistance, you could consider the Schwalbe Pro One TLE in 28 x 559. I have Schwalbe One 28x622 tyres on my old derailleur bike. With the caveat that there are lots of different Schwalbe One models, so it possible that the 28 x 559 may be significantly different from my tyres, I would place the Schwalbe Pro One TLE 28 x 559 just above the Continental Grand Prix 28x559 for rolling resistance, and probably equal for comfort despite being a bit smaller (about 26 mm on my bike). But probably significantly less durable than the Continental and much more expensive.   


Pavel

  • Full Member
  • ***
  • Posts: 107
Re: Tyres for DT Swiss XR425 rims
« Reply #9 on: August 22, 2020, 08:13:18 PM »
what a marvelous source of information some of you are providing here.  It's fantastic!

I had the dyads built up after finding my rims, and stock tires on my Fuji touring bike to be of substandard quality, and also because I wanted to have a dyno hub.  I chose the rims after mentioning some of the details of how I planned to travel.  Mostly I'd rather give up a bit of weight to have more robustness, so he suggested the dyads and I've been very impressed with the wheels, though I'm not sure where more credit is deserved, the rim or the builders skill. 

In any case, they have made me highly pleased with the choice and I've always run prancers in size 37 on them. with the 37mm tires, it looks just about right to my eye, or perhaps a bit wide even.  Now that I've put the rims on the Thorn Audax, and have gone the Scwalbe 1's in size 28 on the rims, the tires look too skinny on the rim for my taste.  I can't say that the Schwalbes are any faster, but they sure are not as comfortable. I'd like to go all the way to the light side, which I've always considered the "dark side" :)  and so would like to find new, much lighter wheels.

But I'm coming around to the viewpoint that 26" wheels have my favorite characteristics, not 700 nor 650B.  So, once again, I will not be fashionable. Are there ANY 26" rim and tyre combination anywhere?  If so, I will stock up a lifetimes supply if tubeless really is the "cats pajamas".  I hope that phrase isn't now like the formerly solid bet, the 26" wheel, out of style. I'd just have to give up on being cool. :D

schw

  • Newbie
  • *
  • Posts: 5
Re: Tyres for DT Swiss XR425 rims
« Reply #10 on: August 26, 2020, 01:50:06 PM »
So I put the 35c Kojaks on the bike at 60/65 psi and went for a shakedown: 20-odd miles on road, dirt, gravel, stones, and grass, in dampish conditions, with around 5 kg in a seat post bag.

They felt fast, sticky, and comfortable on the road. The rear skidded slightly on a poorly-surfaced 14% descent, and over the stones and some of the gravel, but less than I would have expected, and the bike always felt very much under control. That said, the load definitely helped - the rear end is light enough that I have to remember to keep it weighted, which I never thought I'd say about a Rohloff number!

When I got back I checked the tyres and found they only measure 30/30 mm! I definitely noticed less wind resistance and much less tread noise (almost none), and, importantly, a really positive effect on handling. I'd imagined that the decreased trail and wheel flop would more or less cancel each other out, but it turns out that taking away 20 mm of tyre, being equivalent to adding 7 mm of fork rake, has made the steering feel noticeably less floppy and more predictable at both low and medium speeds. (I have since read Danneaux's essential post on manipulating trail through fork rake and tyre size which explains it all: http://thorncyclesforum.co.uk/index.php?topic=4245.msg19567#msg19567) As this fork doesn't take luggage, it seems like a good idea to stick with narrow tyres to keep the trail in the neutral range.

The Kojaks feel and look fine on the rim, and overall I'm very pleased with the outcome. This set may not last me very long, though, given the temptation to take them off pavement..

schw

  • Newbie
  • *
  • Posts: 5
Re: Tyres for DT Swiss XR425 rims
« Reply #11 on: August 26, 2020, 01:53:31 PM »
Andre,
Thanks, it's always instructive to have these limit cases! I will probably never approach them, as my handling skills are likely to always be more of a constraint than my equipment, but I do like to have an idea of how wide the margins are..

Martinf,
Thanks for that - it looks like the 42 mm Supreme outperforms itself in rolling resistance and comfort.
I was very pleasantly surprised by how sure (and fun) the Kojaks seemed on gentle rough stuff. I wouldn't ride them off road in the wet, but at the pressures I use, gravel seems to well within its capabilities.
I haven't used latex tubes since on a road bike years ago when I found the extra smoothness wasn't worth having to reinflate halfway through a ride! I'm sure it's less of an issue with bigger tyres, but for now I use extra lightweight butyl tubes.

Pavel,
I'm guessing it's the Panaracer Paselas in 37c you've been using? I ran a pair of 42c for a while and liked them a lot - buttery and versatile.
I don't have personal experience with tubeless, but SJSC stock the DT conversion kit. I'm sure there are other 26" rims that are marketed as TL compatible, and I understand many others can also be sealed with tape anyway. That said, my impression has been that the benefits of TL may not outweigh the costs with narrower tyres. What surfaces do you ride, what tyre pressures do you run and how often do you get a puncture?
I think you'd be pleased with these or similar rims for a lightweight Thorn build.

martinf

  • Hero Member
  • *****
  • Posts: 727
Re: Tyres for DT Swiss XR425 rims
« Reply #12 on: August 26, 2020, 08:19:27 PM »
I haven't used latex tubes since on a road bike years ago when I found the extra smoothness wasn't worth having to reinflate halfway through a ride! I'm sure it's less of an issue with bigger tyres, but for now I use extra lightweight butyl tubes.

I think most brands of latex tubes might be a bit better nowadays. Mine generally need reinflating every two days or so.

John Saxby

  • Hero Member
  • *****
  • Posts: 1675
Re: Tyres for DT Swiss XR425 rims
« Reply #13 on: August 27, 2020, 02:16:25 PM »
Quote
Are there ANY 26" rim and tyre combination anywhere?

Hey, Pavel, have a look at Velo Orange's offerings -- they're a little way north of you, in Joisey.

I use their rims on both my touring bikes, 700c on my derailleur Eclipse & 26" on my Thorn Raven.  (I use several of their products, incl handlebars.) The rims have been very good, no problems at all.

I use Marathon Supremes on both these bikes, 700 x 35 on the Eclipse, and 26 x 1.6 on the Raven.  (Actual inflated widths are 33mm and 40mm respectively.)  For the riding I do--probably 90% on tarmac, some of that very ratty--I've found they offer the best combination of durability and lower rolling resistance.

Cheers,  John

Pavel

  • Full Member
  • ***
  • Posts: 107
Re: Tyres for DT Swiss XR425 rims
« Reply #14 on: August 27, 2020, 07:06:06 PM »
I used to really like velo-orange products. I've got one or two of their products and was actually thinking of riding my motorcycle up there for a two night camping trip, in order to stop by their store and try out the campeur.

They changed owners a few years ago, and it seems like now they are in some degree of disarray, judging by their website and by two phone calls.  They discontinued the Campeur unfortunately, so now I'm not likely ever to bother anymore. 

It seems like I'll have to keep buying Thorns.  Surly changed the disk trucker into something that I'd not likely find as satisfying now.  I don't want disks but only the disk trucker had the rear mounts for the option of a Rohloff retrofit, so it is a shame that I always wait too long. I rode a LHT two years ago and found it more to my liking in how it rode in a straight line, but dang, nobody puts a proper length steerer except Thorn.

All this change is making me stressed.  I want lighter rims for my RST, for the Audax and keep getting tempted by the new Model Nomad.  Choices, choices, and incompatibilities mix badly with an aging brain.  Isn't cycling supposed to be simple and a way to relax the mind and body?  I'm stressed man.