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#1003078 - 01/02/18 05:45 PM Re: Wethead - sensitivity to tyres [Re: AndyS]  
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AndyS Offline
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AndyS  Offline
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Somerset, Great Britain.
Hi Roger.
So, a couple of different things. Let's talk about the damping issue first. I hear folk raving about the suspension on these new bikes, but I have now ridden a few of them (2014 onward) and really can't agree that it is anywhere near as good as it could be. If the road surface is rippled, or rough, the bike does not dampen those irregularities out fast enough to make for the super smooth ride I am used to on my 1150. It's not really a problem if the bike is upright as the result is mainly a less than comfortable ride (and when coupled with that excuse for a seat it is even worse). Although my suspicion is that if you had to brake really hard under these conditions the stopping distance would increase a little. It becomes more of an issue if you are laid over (banked) to any degree, because the bike is no longer tracking smoothly with the wheels following the irregularities. The bike kind of 'judders' sideways. I don't want to make this sound worse than it is, but it could be way better.

The second issue is the following of over-banding, white lines, road repair grooves, and road joints. If you encounter these features, the bike will try to follow them, a bit like being stuck in tram lines.
Does this explain it any clearer?

#1003094 - 01/03/18 12:04 AM Re: Wethead - sensitivity to tyres [Re: AndyS]  
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Bernie Offline
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Bernie  Offline
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Jax, FL
Hi Andy, I don't know what air pressure you are using in you front tire, but a higher pressure will give you a harder tire (absorbs less bumps and bounces more), then a softer tire.
Also a over inflated tire will have a pointier profile, which will handle like a knifes edge, instead of having the larger, flatter contact patch of a tire with lower air pressure.
As you know in the past BMW used to recommend a range of air pressures, based on load on the bike. Why the stopped doing that, I am sure a lawyer knows.
But on the 05-13 R1200RT they used to recommend for the same size and brand tire 32-26 PSI cold.
So depending on how heavy you are with all your gear on and how much stuff you carry with you when you ride in your cases and tank bag, I would recommend lowering your air pressures.
It may very well help you with your problem and I don't think the difference in mileage in wear is going to be a big enough factor.
On my 07 RT, my front tires lasted just as long running 32 psi as it did using 36 psi.
Now if you are more on the heavier side of the scale, setting the shocks up for more preload (rider with bags or rider and passenger) will level the bike out and let the shocks work in a proper range.
The shock pistons have to have enough room above and below them to move and let the oil handle the damping.
Also increasing the preload on the rear shock adds more weight to the front tire, letting it grip the road surface better and possible prevent it from following all the painted stripes.


Bernie
Jax, FL
2018 R1200RT, Alpinweiss, starting out fresh.
2007 R1200RT, Double Silver 188,700 Smiles, SOLD
2000 R1100RT, Opal 104,000 Smiles, SOLD
BMW-MOA, BMW-RA,
AMA, BMW-NEF,
#1003113 - 01/03/18 09:25 AM Re: Wethead - sensitivity to tyres [Re: AndyS]  
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AndyS Offline
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AndyS  Offline
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Somerset, Great Britain.
Hi Bernie, thanks for the input, but you may also have seen my comments on roger 04rt's thread, where we are discussing handling issues. So, for the time being I am playing with tyre pressures to overcome issues of the bike tracking badly along white lines, road cracks, road surface repairs and joins. I have not dropped the pressures below 36 in the front, but I may briefly give it a go to see if it changes things. As with most bikes it is worse when the tyres are cold (as in just starting off for a ride), but improve somewhat as they warm up.

#1003136 - 01/03/18 08:12 PM Re: Wethead - sensitivity to tyres [Re: AndyS]  
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roger 04 rt Offline
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roger 04 rt  Offline
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Naples FL & Cape Cod
Originally Posted by AndyS
Hi Roger.
So, a couple of different things. Let's talk about the damping issue first. I hear folk raving about the suspension on these new bikes, but I have now ridden a few of them (2014 onward) and really can't agree that it is anywhere near as good as it could be. If the road surface is rippled, or rough, the bike does not dampen those irregularities out fast enough to make for the super smooth ride I am used to on my 1150. It's not really a problem if the bike is upright as the result is mainly a less than comfortable ride (and when coupled with that excuse for a seat it is even worse). Although my suspicion is that if you had to brake really hard under these conditions the stopping distance would increase a little. It becomes more of an issue if you are laid over (banked) to any degree, because the bike is no longer tracking smoothly with the wheels following the irregularities. The bike kind of 'judders' sideways. I don't want to make this sound worse than it is, but it could be way better.

The second issue is the following of over-banding, white lines, road repair grooves, and road joints. If you encounter these features, the bike will try to follow them, a bit like being stuck in tram lines.
Does this explain it any clearer?


Hi Andy, Yes, that’s much clearer. Thanks.

#1003210 - 01/05/18 07:30 AM Re: Wethead - sensitivity to tyres [Re: BigTup]  
Joined: Sep 2000
Posts: 491
Red Offline
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Red  Offline
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Burns, OR
Ear plugs. That way you get good handling and no noise!


Red,
"The trouble with internet quotes is that you can never know if they are genuine." -- Julius Caesar
#1003217 - 01/05/18 06:53 PM Re: Wethead - sensitivity to tyres [Re: AndyS]  
Joined: Nov 2014
Posts: 36
Lucky Dave Offline
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Lucky Dave  Offline
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Posts: 36
Encinitas,Ca
I don't think RTs are that sensitive to tires, but they're VERY sensitive to inflation pressures. I run mine at 37/43. The front is especially important, at 37 it steers wonderfully, at 36 it's OK-ish and at 35 it steers like it has a flat tire.

Last edited by Lucky Dave; 01/05/18 06:54 PM.

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