Tandem Tyre Choice in 26 x 2.0 ?

[Brucey]

I saw that chart before but it wasn't what I was trying to find exactly so I didn't think about its implications.

In the context of this discussion for a 50mm tyre it recommends pressures of 2.5, 4.0, 5.0 bar for bodyweights of 60kg, 85kg and 110kg respectively. Presumably there is some (unknown) allowance built into this advice for the weight of the bike and luggage, plus the weight distribution not being perfect between the wheels.

But what it means is that they 'recommend' a pressure which is in excess of the maximum allowable for some of their 50mm tyres, even at a load under the stated maximum. For example the 50-559 Marathon Supreme has a maximum allowable pressure of 4.5bar and a max load (per tyre) of 120kg.

Lots of inconsistencies!

cheers

[reohn2]

I saw that chart before but it wasn't what I was trying to find exactly so I didn't think about its implications.

In the context of this discussion for a 50mm tyre it recommends pressures of 2.5, 4.0, 5.0 bar for bodyweights of 60kg, 85kg and 110kg respectively. Presumably there is some (unknown) allowance built into this advice for the weight of the bike and luggage, plus the weight distribution not being perfect between the wheels.

But what it means is that they 'recommend' a pressure which is in excess of the maximum allowable for some of their 50mm tyres, even at a load under the stated maximum. For example the 50-559 Marathon Supreme has a maximum allowable pressure of 4.5bar and a max load (per tyre) of 120kg.

Lots of inconsistencies!

cheers

As I posted before I go off experience,many appear to just whack in as much air as it says on the sidewall,i'm confent the Berto scale is sound within a couple of PSI.

[pwa]

Surely, as a tandem puts the weight of two people on a tyre usually designed with the load of one person in mind, you are going to put more air in than you would with the same tyre on a solo bike. And that will push you towards the stated max. I think the Paselas I used on our tandem had a stated 75psi max, and that is more or less what I put in them to get the best ride experience on-road. It seemed like enough but not too much. The weight of two people on them made them feel smooth over chip n seal.

[Brucey]

As I posted before I go off experience, many appear to just whack in as much air as it says on the sidewall,i'm confent the Berto scale is sound within a couple of PSI.

for comfort that is not far off. The question in my mind is that (especially in tandem use), if you run pressures at some lower value, you are also reducing the load rating of the tyre and that may not be safe.

I'll say it again; the load rating of the tyre only applies when the tyre is fully inflated to maximum allowable pressure.

At lower pressure the tyre will not safely bear the maximum load. Schwalbe's recommendations are for higher pressures than 'comfort' (Berto) might dictate and part of that is almost certainly tyre safety related.

cheers

[reohn2]

As I posted before I go off experience, many appear to just whack in as much air as it says on the sidewall,i'm confent the Berto scale is sound within a couple of PSI.

for comfort that is not far off. The question in my mind is that (especially in tandem use), if you run pressures at some lower value, you are also reducing the load rating of the tyre and that may not be safe.

I'll say it again; the load rating of the tyre [b]only applies when the tyre is fully inflated to maximum allowable pressure.[/b]

At lower pressure the tyre will not safely bear the maximum load. Schwalbe's recommendations are for higher pressures than 'comfort' (Berto) might dictate and part of that is almost certainly tyre safety related.

cheers

I can't find that anywhere on the Schwalbe site.

[Brucey]

as linked in a previous post (which included page numbers). It clearly states 'Maximum load (per tyre at maximum pressure)'.

All tyres are rated this way and none will safely bear such high loads at lower pressures.

Were it possible to have a higher load or a higher pressure neither would be a 'maximum'.

I do think it is remiss that they don't explain this more fully but having said that, Schwalbe might not be doing very well but they are still doing better than most other bicycle tyre manufacturers.

cheers

[pwa]

As I posted before I go off experience, many appear to just whack in as much air as it says on the sidewall,i'm confent the Berto scale is sound within a couple of PSI.

for comfort that is not far off. The question in my mind is that (especially in tandem use), if you run pressures at some lower value, you are also reducing the load rating of the tyre and that may not be safe.

I'll say it again; the load rating of the tyre [b]only applies when the tyre is fully inflated to maximum allowable pressure.[/b]

At lower pressure the tyre will not safely bear the maximum load. Schwalbe's recommendations are for higher pressures than 'comfort' (Berto) might dictate and part of that is almost certainly tyre safety related.

cheers

I can't findnthat anywhere on the Schalbe site.

How do you decide when a tyre is too soft? Surely you can't just go off a chart, you must apply some experience, looking at the shape the bottom of the tyre adopts when loaded, how far off the ground the vulnerable sidewall is, how much the bike is inclined to bouncing and so forth. On a tandem, applying those sorts of consideration tend to push me towards the max pressure, which still feels soft due to the weight pressing down on a tyre designed for solo bikes.

[Brucey]

the other thing is that what feels/looks perfectly OK to start with can have little margin for error and also may not work at all well when the conditions change slightly. So downhill with the brakes on, you may (on a solo) have most of your weight on the front wheel and likewise most on the rear when climbing. Such effects are not likely to be as extreme on a tandem but there will still be variations.

Personally I find that with wide soft tyres the rot sets in when cornering and riding out of the saddle; once the tyre starts squirming around I am pretty sure I am losing grip and the tyre is being overworked, even if it feels 'nice and comfy' when riding in a straight line. Most MTB rear tyres I have owned have started to fail in the sidewall through seeing high loads at low pressures, well before the tread is worn. IME it doesn't take much to push a tyre over the edge on a tandem; I am very often surprised at what folk seem to get away with.

cheers

[reohn2]

How do you decide when a tyre is too soft? Surely you can't just go off a chart, you must apply some experience, looking at the shape the bottom of the tyre adopts when loaded, how far off the ground the vulnerable sidewall is, how much the bike is inclined to bouncing and so forth. On a tandem, applying those sorts of consideration tend to push me towards the max pressure, which still feels soft due to the weight pressing down on a tyre designed for solo bikes.

Tyre drop (15% according to Berto' chart)is a fair indication,TBH I arrived at similar figures though slightly higher by trial and error over a few hundred miles before reading the Berto graph.
I must confess it needed a certain amount of courage riding such low PSI's,but it works and works very well.

Yesterday I did 47miles from home in Lowton,80% of it on rocky tracks,hardpack and gravelly trails and towpaths(the rockiest bits were the climb up to the Dove Tower near the Pike from Rivington Village and across on the top unmettled and equally rough track(marked on the map as Belmont Road) to bring me out onto Rivington Rd where I descended into Belmont,A675 to and through Roddlesworth Wood,an area you know well)the longest bit of tarmac on the ride was from Belmont village to Roddlesworth Wood.On the descent into Belmont I registed 38mph on the Garmin 810
I was on the Vagabond with Jones type loop bars,700x50mm(47x47 actual widthxheight) Marathon Supremes @ 20psi front 40Psi rear,total load was 104kg with an estimated 40f/60%r tyre load and perfect for the terrain and not draggy on tarmac,average speed was 9.8mph.
The bike handles perfectly with an average speed on level tarmac or good hard pack or gravel is usually between 14 and 15mph.

I'm impressed with the Supremes performance and have covered somewhere around 800 miles on them at these TPs,they're showing very little signs of wear yet other than only a couple of superficial cuts and no punctures(that's done it ).
As a confirmation of TPs,theres a steel bridge over the canal at Wigan with a 23cm(9inch) step on one side which I usually hop up the front wheel over and ride up,on two occasions when tired I've miss timed lifting the front wheel and hit the corner of the step square on almost stacking in the process .
Both times I've examined the tyre thinking I could have damaged the sidewalls with no signs of damage at all and no snakebites,both incidents have confirmed the tyres are inflated correctly.
As I say I can only speak from experience

[IanA]

We've been using Supremes on tandems for about the last 8 years, initially on 700c but now on 26''. Use is generally day rides and multi-week touring. I recall 3 punctures in one trip but no other issues. At the moment using 26 X 1.6. Have found them to be good on road and gravel tracks. They roll well, are comfortable and reliable. A similar question was recently asked on the Tandem Club Facebook page and Chris J also recommended the Supremes.

Hi Ian, good to read of your experience with Supreme 26x1.6 which we have fitted to our tandem also. I would be interested in your experience with tyres pressures. I've experimented a fair bit and generally run them at 60psi f+r for an all up weight of around 175kg.

Thanks

iandsud, I normally don't pay much attention to pressure, just what feels/looks right. But I have just checked and it was below 40psi which is a bit soft and was intending to add a bit more before the next ride. I pumped it up to 60psi which feels about the top end I would normally do. So probably normally running 50-60psi. On tour that is probably about what I can easily get in with a small pump, after a flight for instance. Our all up weight for a day ride, people, tandem and rack pack, is about 145kg. Weight would be more when touring (credit card, not camping) but I don't think we would be going much above 60psi.

[RickH]

As I posted before I go off experience,many appear to just whack in as much air as it says on the sidewall,i'm confent the Berto scale is sound within a couple of PSI.

I dread to think what 38mm Voyager Hypers (marked 40-622) would ride like if you took any notice of the pressures on the tyres - they say 60psi minimum & 90psi maximum! That surely must be an error? I run mine at 35F/40R. 40mm WTB Nanos (also marked 40-622), that I also run, say 35 - 55psi on them.

[reohn2]

As I posted before I go off experience,many appear to just whack in as much air as it says on the sidewall,i'm confident the Berto scale is sound within a couple of PSI.

I dread to think what 38mm Voyager Hypers (marked 40-622) would ride like if you took any notice of the pressures on the tyres - they say 60psi minimum & 90psi maximum! That surely must be an error? I run mine at 35F/40R. 40mm WTB Nanos (also marked 40-622), that I also run, say 35 - 55psi on them.

IMO your pressures sound about right for a lightweight such a as yourself(i'm guessing your about 60 to 65kgs?).
TBH I'd never looked at the sidewall blurb,but I've just been to the Holy place that is the Voyager tyre stash and you're right 60to90psi EEK!

[Bonefishblues]

As I posted before I go off experience,many appear to just whack in as much air as it says on the sidewall,i'm confident the Berto scale is sound within a couple of PSI.

I dread to think what 38mm Voyager Hypers (marked 40-622) would ride like if you took any notice of the pressures on the tyres - they say 60psi minimum & 90psi maximum! That surely must be an error? I run mine at 35F/40R. 40mm WTB Nanos (also marked 40-622), that I also run, say 35 - 55psi on them.

IMO your pressures sound about right for a lightweight such a as yourself(i'm guessing your about 60 to 65kgs?).
TBH I'd never looked at the sidewall blurb,but I've just been to the Holy place that is the Voyager tyre stash and you're right 60to90psi EEK!

A safety deposit box somewhere, I'm guessing

[reohn2]

I dread to think what 38mm Voyager Hypers (marked 40-622) would ride like if you took any notice of the pressures on the tyres - they say 60psi minimum & 90psi maximum! That surely must be an error? I run mine at 35F/40R. 40mm WTB Nanos (also marked 40-622), that I also run, say 35 - 55psi on them.

IMO your pressures sound about right for a lightweight such a as yourself(i'm guessing your about 60 to 65kgs?).
TBH I'd never looked at the sidewall blurb,but I've just been to the Holy place that is the Voyager tyre stash and you're right 60to90psi EEK!

A safety deposit box somewhere, I'm guessing

It's a sekrit

[jon.k]

Another vote for duremes here. Bought from SJS, they roll ok and cope well with light off-road tracks.

Confusingly, for a tandem on 2.00" tyres, Thorn/SJS themselves recommend 50 / 58 psi front / rear, with "absolute max" of 80 psi.

http://www.sjscycles.com/thornpdf/Thorn ... oHiRes.pdf (page 10 has their chart).




Can anyone tell me where to find the schwalbe weight limit table? I'd like to find out what Durano Plus tyres will take.