RE: Anyone know what tiers will be fitted - 4

RE: Anyone know what tiers will be fitted

I can no longer resist, apologies in advance!

"Round and Black" would be my guess and as I lack the expertise to state one make is better than another I am usually happy to have new tyres, even better on a new bike.

Started back on bikes 1997 after a break since 1984 - first road bike 1970 Yamaha 125 YASI - teflon tyres, non-stick brakes and muliple first year crashes and near misses, worst of which I skidded past a stopped bus and the large removal van drove into roadside earth banking to miss me (thanks - he saved me for a head-on death crash I am sure!) last bike in 84 was the Yam XS1100E, then XS1100S. My XS750 triple was lethal on road runner tyres in the wet, scared me so much it went after 4 summer months where I knew it would kill me in winter, so despite finacial hit it went in px for the 1100E.

Since 1997, returned with Kawasaki ZRX1100 then the 1200, and from 2005 bmw bikes ST, S, R. RS, RS I have taken each bike as delivered and each one has been advertised as better than the last.
Better tyres, Better Brakes, Better Performance, Better fuel range, Better safety, Better traction control, Better lights etc.
If there was a difference between tyres I can only say all of these new ones never had me worried, dry roads or wet, some needed replacing earlier (1200S) but most did 10,000 miles.
I know if an error occurrs, speed too high, road mis-read, SMIDSY avoidance, I must relax and look where I want to go, pray to the road gods knowing this bike has more ability (in the right hands) than I have and am thankful to all the worlds road testers (NOT magazine writers) who test our equipment beyond most of our abilities.
Maybe track riders need the 'very best/latest improved' but for road users does it make that much difference?
Changing to Michelin roads to version 5 having had earlier road, road 3 /4 or Metzeler, Bridgestone, Continental I know new tyres are always better than the worn ones removed so once the 600 mile smooth running in! is completed I would not be bothered which make bmw have had a good deal on.
Just enjoy the new bike and hope for improved travel options next year.

I've had Z8s, PR4s and RS2s on my RS, couldn't put a fag paper between 'em.

I have always figured that BMW just picks a tire that is available in quantity, meets their required usage and can be purchased in volume at the lowest cost. Lately most of the time that seems to be the Z8.

Zitat von wessie im Beitrag #49

---

Zitat von Richard230 im Beitrag #48

---

I have always figured that BMW just picks a tire that is available in quantity, meets their required usage and can be purchased in volume at the lowest cost. Lately most of the time that seems to be the Z8.

---

they follow the same protocol as me - stay 1 tyre revision behind the latest, allegedly better version. Working very well for me with the Avon Storm 3 (not the newer ST Spirit) on the RS and Bridgestone S21 Hypersport (not the newer S22) on my XR. I am happy with the tyre performance on both bikes and have fitted a 2nd set of each to the respective bikes. I took the XR on a 50 mile business trip today in bright sunshine, through the Forest of Dean on very new S21 and I must say, today has been one of my best days at work for a long time!

---

Zitat von Ray im Beitrag #44

---

Zitat von Mr. 36654 im Beitrag #42

---

You're assuming the location of the load is fixed and the location of the rear wheel is moving aft

---

I agree, but assumptions are necessary in the absence of data. I don't understand your "and the location of the rear wheel is moving aft". I said as the wheelbase get's longer ... that means moving aft.

---

I think that's what I said ...

Here is a recent tire review and they used an R1250RS as the testing vehicle. Guess what? All of the tires are great: https://www.motorcyclenews.com/advice/be...-touring-tyres/

Dunlop has just introduced an RS4 model, but at a much higher price than the RS3. Here is a report about these new tires, of course you have to maneuver around the popups to read the short story:
https://ultimatemotorcycling.com/2020/08...k-8-fast-facts/

Zitat von wessie im Beitrag #54

---

Zitat von Richard230 im Beitrag #53

---

Here is a recent tire review and they used an R1250RS as the testing vehicle. Guess what? All of the tires are great: https://www.motorcyclenews.com/advice/be...-touring-tyres/

Dunlop has just introduced an RS4 model, but at a much higher price than the RS3. Here is a report about these new tires, of course you have to maneuver around the popups to read the short story:
https://ultimatemotorcycling.com/2020/08...k-8-fast-facts/

---

Interesting comment about side walls. It's all been about making them stiffer for big bikes but it seems they have listened to customer complaints about harsh rides as the sidewalls are integral parts of the suspension, absorbing some of the energy from road undulations. Seems they have modified the bead to make it more robust. Might make tyre changes more interesting...

---

Zitat von Mr. 36654 im Beitrag #51

---

Ignoring braking action, the load distribution on the tires is a simple function of the distance from the front tire contact patch to the lateral location of the center of gravity or mass of the vehicle and load (i.e., rider and luggage). If the CG is located at the midpoint of the wheelbase, the load will be evenly split between the front and rear tires. That's your sum of moments. In the following figure, when L_1 = 0.5 L_WB, the rear wheel load (R_R) equals 50% of the total weight (W) and the front wheel load (R_F) equals the rear wheel load. Only if L_WB is increased relative to L_1 (L_1 / L_WB less than 0.5) will the load on the rear tire be reduced from half of the total weight.
(Link Removed)
Now, in the case of braking and ignoring suspension compression, we have the additional load due to the deceleration of the effective mass (i.e., bike, rider and luggage). Going old-school, I'll represent mass as the total weight (W) divided by gravity (g). Deceleration is the change in velocity (Delta_V) within a given time period (Delta_t). As shown in the following figure, this deceleration load yields a moment about the front tire contact patch (Point "0") which is opposite the moment resulting from the total weight. If you decelerate too rapidly, place your load too high or too far forward, you'll reduce the load at the rear tire contact patch and, in the extreme, do a stoppee. If maximizing rear tire load is your goal, the bike must be designed to have the CG at a low height and a relatively far aft. In other words, like a cruiser.
(Link Removed)
Personally, I prefer a bike with a shorter wheelbase (remember, I'm an American using American references) to enjoy maneuverability on twisty roads. I'm also 6-1 and 200-lbs which means I prefer a higher seat to elevate my added mass contribution. So, for braking, especially in turns, brake before initiating the lean and shift your weight aft when you brake. Trail braking thru the turn is fine, but rear tire traction will be limited by physics. If the rear tire seems "squirrelly" gradually release any rear brake you're applying. Applying more brake pressure in this scenario is only going to result in less rear wheel traction

---

[quote=Mr. 36654|p30856][
Ignoring braking action, the load distribution on the tires is a simple function of the distance from the front tire contact patch to the lateral location of the center of gravity or mass of the vehicle and load (i.e., rider and luggage). If the CG is located at the midpoint of the wheelbase, the load will be evenly split between the front and rear tires. That's your sum of moments. In the following figure, when L_1 = 0.5 L_WB, the rear wheel load (R_R) equals 50% of the total weight (W) and the front wheel load (R_F) equals the rear wheel load. Only if L_WB is increased relative to L_1 (L_1 / L_WB less than 0.5) will the load on the rear tire be reduced from half of the total weight.
............ /quote]

You lost me somewhere around the end of this first paragraph! I shall have to re-read it several times!

Chris

Back to tyres, I’ve just had a pair of Avon Storm3DXM fitted today, £200 on loose wheels. Seemed a good price and although not the sexiest/latest tyres out there, they look great to me. Will be interesting to see how they perform and their longevity after 2 sets of Metzeler Z8’s (I was quoted £230 for those and £280 for Z8’s).

Zitat von tony.parker im Beitrag #56

---

Zitat von Mr. 36654 im Beitrag #51

---

Ignoring braking action, the load distribution on the tires is a simple function of the distance from the front tire contact patch to the lateral location of the center of gravity or mass of the vehicle and load (i.e., rider and luggage). If the CG is located at the midpoint of the wheelbase, the load will be evenly split between the front and rear tires. That's your sum of moments. In the following figure, when L_1 = 0.5 L_WB, the rear wheel load (R_R) equals 50% of the total weight (W) and the front wheel load (R_F) equals the rear wheel load. Only if L_WB is increased relative to L_1 (L_1 / L_WB less than 0.5) will the load on the rear tire be reduced from half of the total weight.
(Link Removed)
Now, in the case of braking and ignoring suspension compression, we have the additional load due to the deceleration of the effective mass (i.e., bike, rider and luggage). Going old-school, I'll represent mass as the total weight (W) divided by gravity (g). Deceleration is the change in velocity (Delta_V) within a given time period (Delta_t). As shown in the following figure, this deceleration load yields a moment about the front tire contact patch (Point "0") which is opposite the moment resulting from the total weight. If you decelerate too rapidly, place your load too high or too far forward, you'll reduce the load at the rear tire contact patch and, in the extreme, do a stoppee. If maximizing rear tire load is your goal, the bike must be designed to have the CG at a low height and a relatively far aft. In other words, like a cruiser.
(Link Removed)
Personally, I prefer a bike with a shorter wheelbase (remember, I'm an American using American references) to enjoy maneuverability on twisty roads. I'm also 6-1 and 200-lbs which means I prefer a higher seat to elevate my added mass contribution. So, for braking, especially in turns, brake before initiating the lean and shift your weight aft when you brake. Trail braking thru the turn is fine, but rear tire traction will be limited by physics. If the rear tire seems "squirrelly" gradually release any rear brake you're applying. Applying more brake pressure in this scenario is only going to result in less rear wheel traction

---

Hi Mr.36654,

An informative and mostly complete response.

You have, for reasons of simplicity for the common rider i assume, ignored the weighting variations due to vertical undulations in the road surface.

For the more technical and pedantic among us, i wonder if you could include your parameters for this and recalculate.
Naturally, of course, accounting for vertical distance, period of undulation, and the varying undulation frequency as observed on the bike as a function of velocity..........

Perhaps even accounting the resultant longitudinal oscillation and corresponding inertia as a function of total sprung and unsprung mass. (Or is this going too far.......?)

Kind regards from Tassie,

Cheers :D

---