Front tire R18 FE (19"/ 120 wheel)

[Ulrich]

I just checked with an AI chatbot and it's supposedly the same as on my bike. 36 psi front / 42 rear

I am sorry ... but i tend to trust the specs that a manufacturer casts on his tires a whole lot more than a hallucinating AI/Chat Bot ... I will see what BMW recommends ... looks like 36 PSI
The manual says:

(although I find it funny that there is a con-rod and piston depicted by 'Front Tire Pressure')
And the plaque on the bike itself states the same ...


I will check when I get back home and see what it is and maybe up it just a bit to 38 or so ...

 

[Petrus]

I will check when I get back home and see what it is and maybe up it just a bit to 38 or so ...

That difference is irrelevant.

 

[Noelpolar]

My original tyre cupped like that. Mostly with lighter fork oil, new springs and emulators.... lots of hard riding and front brake use. I'm running an adventure tyre that I've had in the shed for a few years now, must have a look at how that is fairing.... almost fell into the first few corners with that.

I'm not aware of a pressure on the side off the tyre as such..... isn't there just the max pressure at rated max load? Not easily "relevant" to each application.

I do often wonder how a rear tyre can be optimised for a single pressure when the load on it can vary by 30% ( one 85kg rider or 2 big people 200kg) and not take into accout all the other normal stuff one considers when determining an optimal tyre pressure. Anyway, I assume BMW just uses the KISS principle for lazy people and likes as little corporate risk as possible.... at the expense of harshness and non optimal tyre life for the user.

 

[Rufus]

Tbh Ulrich I think those mileages are pretty good despite the wear (cupping), I don’t think I’ve ever got more than 8k out of a front tyre on any bike I’ve owned no matter what brand. These are very heavy bikes with a very long wheelbase and the contact patch is tiny so the tyre will be doing a lot of work braking, turning and all the rest of it. It’s great that you document things for everyone’s benefit though

 

[Petrus]

I'm not aware of a pressure on the side off the tyre as such..... isn't there just the max pressure at rated max load? Not easily "relevant" to each application.

I do often wonder how a rear tyre can be optimised for a single pressure when the load on it can vary by 30% ( one 85kg rider or 2 big people 200kg) and not take into accout all the other normal stuff one considers when determining an optimal tyre pressure. Anyway, I assume BMW just uses the KISS principle for lazy people and likes as little corporate risk as possible.... at the expense of harshness and non optimal tyre life for the user.

On a performance bike/car with track tyres it makes a húge diffence: 0.2 bar more/less up front can change to/from understeer/oversteer markedly.

On the R18 it is indeed all about load and yes to the max load.
Be aware though that the max load of the R18 models is rather limited so the difference between one sturdy rider and the max is not that much and in the light of the overall weight less still.
The front tyre much the same. I would not faff with it; just stick to spec.

That observed I díd up mine a miff for sidecar use. The max traction is not so much of an issue with a learner wheel and it reduces understeer júst that little bit.

 

[Ulrich]

Tbh Ulrich I think those mileages are pretty good despite the wear (cupping), I don’t think I’ve ever got more than 8k out of a front tyre on any bike I’ve owned no matter what brand. These are very heavy bikes with a very long wheelbase and the contact patch is tiny so the tyre will be doing a lot of work braking, turning and all the rest of it. It’s great that you document things for everyone’s benefit though

Thanks! I was thinking the exact same thing ... back in the days (waaaay back) I was happy if a tire lasted me 3 to 5000 miles ... I wrote different bikes and a lot more 'bonkers' ... I was hoping these big cruisers would have tires to last a bit longer. But the 'cupping' and really uneven wear is bugging me. I did check the pressure yesterday and it was 36 PSI with a hot tire ... I added a couple of pounds (upping it to 38) but that really (IMO) can't be the cause. I think I will squeeze another 1 or 2000 miles out of this tire and then go back to the 'Cruisetec' it did cup ... but overall wore and held up the best.

Oh and before somebody suggests a bent rim ... I did run a dial indicator on it and the run out is very little ... not any more or less than any other front wheel that I can recall.

 

[Rufus]

Thanks! I was thinking the exact same thing ... back in the days (waaaay back) I was happy if a tire lasted me 3 to 5000 miles ... I wrote different bikes and a lot more 'bonkers' ... I was hoping these big cruisers would have tires to last a bit longer. But the 'cupping' and really uneven wear is bugging me. I did check the pressure yesterday and it was 36 PSI with a hot tire ... I added a couple of pounds (upping it to 38) but that really (IMO) can't be the cause. I think I will squeeze another 1 or 2000 miles out of this tire and then go back to the 'Cruisetec' it did cup ... but overall wore and held up the best.

Oh and before somebody suggests a bent rim ... I did run a dial indicator on it and the run out is very little ... not any more or less than any other front wheel that I can recall.

I’ve had a couple of R850R roadsters in the past and put 17k miles on one of them, changed the front tire twice on it while I had it. Lovely bike btw. That had noticeably more wear on the sides than the crown of the tyre and it was uneven (felt wavy) very similar to your pictures. I remember vividly how fresh the bike felt with the new tyres on, it felt a lot more plush and rolled into a bend so much more sweetly than before. You don’t realise how much the tyres go off (with regular use) because it’s so gradual.

 

[Ulrich]

So ... a quick foot note to this. I did recheck the tire pressure cold and it was at 35 PSI ... that should be well within tolerances (unless you are in Moto GP) ... so I did go to 39 pounds cold and I noticed something ... more often than not when I coast down to a stop I take my hands off the bars and lean back, in the past I had a front end wobble (not much, just noticeable) and I contributed that the 2 very large pistons firing left right (or right left ... depends on when you start counting ) and thought noting off it ... now since I upped the pressure that seems to be gone ... very odd, I didn't think that a couple pounds back and forth would make a noticeable difference ... maybe? I will keep an eye on it. The tire is already worn, but maybe it will live a bit longer that way ... time will tell.

 

[Petrus]

So ... a quick foot note to this. I did recheck the tire pressure cold and it was at 35 PSI ... that should be well within tolerances (unless you are in Moto GP) ... so I did go to 39 pounds cold and I noticed something ... more often than not when I coast down to a stop I take my hands off the bars and lean back, in the past I had a front end wobble (not much, just noticeable) and I contributed that the 2 very large pistons firing left right (or right left ... depends on when you start counting ) and thought noting off it ... now since I upped the pressure that seems to be gone ... very odd, I didn't think that a couple pounds back and forth would make a noticeable difference ... maybe? I will keep an eye on it. The tire is already worn, but maybe it will live a bit longer that way ... time will tell.

matches mine albeit with the sensitivity to road 'snakes' and the like. Now with the rig have it highish to reduce understeer.

 

[Ulrich]

So just to pick this back up ... I have gone to 40 psi in the front (away from 36) and it definitely has improved things ... it even seems to 'clean up' the tire and even out the wear ... no problem, now I know ... just run a bit higher pressure ... easy!

 

[brownbandit]

Both on my previous roctane and now bagger model, I’ve also experienced short life on the front tire which drives me crazy.

I am going to eventually redo the front forks with racetech gold emulators alongside new springs and oil and see if that helps out.

These bikes feel like they’re on stilts.

 

[AdventureBoy]

I have a standard R18, I run 40lbs in the front to try and make those horrible original tyres work a bit better, my bike only has 4,000ks on it and the front is just starting to 'cup'.
I'm right now getting rid of the Commander III's, they are horrible, noisy, lack grip and have a horrible profile. I have fitted a new front had had a short test ride and it feels much nicer already. The new rear is going on today - Pirelli Night Dragons.
The pic shows the difference of profile of the rear. I'm sure it will be a nicer ride and turn in a lot easier.

 

[Noelpolar]

I have 2,000km now on my ex scrambler adventure tyre.... all going well.... bike almost "drops" into corners, great grip. Probably won't last long, but it was free.

 

[AdventureBoy]

Will test the new rear today.

The new front after a 30min test ride.

 

[HUNTS]

So just to pick this back up ... I have gone to 40 psi in the front (away from 36) and it definitely has improved things ... it even seems to 'clean up' the tire and even out the wear ... no problem, now I know ... just run a bit higher pressure ... easy!

Rode today after upping to 39 front, 44 rear… totally agree with Wise Ulrich.

 

[AdventureBoy]

Is there a thread/topic just for tyres in this forum, I'd like to post my impression of my new tyres.

 

[Ulrich]

Is there a thread/topic just for tyres in this forum, I'd like to post my impression of my new tyres.

Garage/Mechanical Help should work IMO ...