Z6 Tire Questions

[Ninja_Vidal]

I was readin the recomendations on the site for Tires, and after reading how many time CP suggested Z6 tires, I ordered a set from a group buy my friends organized.

My questions are:

1. Are all Z6 Roadtech tubless? I noted that my current dunlops say tubless on them.

2. Has anyone heard of problems with tread separation. One guy said they were great tires, but had problems with tread separation.

3. I'm going from 110/70 & 140/80 Dunlops to Z6 120/170 & 150/70. What should i expect? (will the bike be higher? harder to lean? etc ..)

thanks in advance

-Vidal

[woobie]

Other than the one comment with links on the GTA site I've never heard of any problems with the Z6s.

My first set I swapped out with 16,000kms on them, here's a pic of the new and old set http://home.cogeco.ca/~kdoubleday/16Kkms.jpg .

The ones I have on now have 10,000kms on them. I have had zero problems with them so far and wll probably get abother set this summer.

BTW here's the links originally poste don the GTA site

http://www.southbayriders.com/forums/showthread.php?p=140539#post140539

This one I think was a Z4'

http://www.fjrowners.com/discus/messages/9/33488.html?1112770143

[The CyberPoet]

Thanks for pointing out that FJR thread (and the other thread it linked to as well).

The only times I've ever seen any tire go out like that involved a specific set of circumstances:
(A) when the tire was already at the end of it's life cycle (less than 1mm minimal tread left in the center) AND
(B) had been run too low on air for quite some time (running over-heated) AND
(C) someone hit the front brake hard enough to lock the tire on one particular patch at some point in the past... (which is where the blister develops).
All of which goes along with the whole "I had a blister and was nursing it home" comments by the owner of that bike (and comments by other owners about bad rain handling in related threads). Blisters come from running tires way too hot, and that means way too far with too much load at too low a pressure setting. Too low a pressure could be a particularly nasty problem on the FJR, as they are damn heavy (about 135 lbs heavier than a Kat, at 645 lbs wet Source: RiderReport.com); as a result, the FJR's got a specialized version of the Z4 and Z6 tires frm the factory which are supposed to be unique to their heavier load bias... If he got a stock one instead (dealer installed just any old Z6, whatever), that could have been the issue right there.

As for me, I'm on my 5th set of Metzelers on a Kat right now and just ordered a replacement Z6 front off ebay because someone had a few new ones at a dirt-cheap price ($75 delivered; I'll store till I need it). I've never had any issues with plies delaminating, uneven surface wear, bubbling, or other questionable-quality issues on a Kat with any of the Metzeler Z-series products. And I've taken them for long trips (up to 3k miles a trip), including with passenger and saddlebags loaded on. Just remember to adjust your air pressure to match your load weight...

Cheers,
=-= The CyberPoet

[The CyberPoet]

Re: Z6 Tire Questions

I guess I never answered some of your specific questions...

1. Are all Z6 Roadtech tubless? I noted that my current dunlops say tubless on them.

Yes. No "Z" series tire in Metzeler's line-up is tubed.

3. I'm going from 110/70 & 140/80 Dunlops to Z6 120/170 & 150/70. What should i expect? (will the bike be higher? harder to lean? etc ..)

Switching from old dunlops, you should expect the Z's to change seat height by a few millimeters (nothing significant), the handling to be much sharper (easier to get it into and out of leans), the grip to be higher, the wet weather behavior to be better, and finally, your braking distances to be reduced.

If you post your approximate total load weight, I will be happy to recommend specific tire pressures. The ideal is to maintain the same tire deflection amount (the amount the tire flattens on the bottom) when you are on the bike as the bike would have have without you on it when it's at 33 psi front, 36 psi rear. This generally means somewhere around 36 to 38 psi front and 38 to 40 psi rear, depending on your combined load weight (you, gear, tools, saddlebags, passengers, etc).

Cheers,
=-= The CyberPoet

[Ninja_Vidal]

Re: Z6 Tire Questions

If you post your approximate total load weight, I will be happy to recommend specific tire pressures. The ideal is to maintain the same tire deflection amount (the amount the tire flattens on the bottom) when you are on the bike as the bike would have have without you on it when it's at 33 psi front, 36 psi rear. This generally means somewhere around 36 to 38 psi front and 38 to 40 psi rear, depending on your combined load weight (you, gear, tools, saddlebags, passengers, etc).

Cheers,
=-= The CyberPoet

Thanks CP ... I'd expect between 200 and 250 lbs on the bike at any time.

So i'm not supposed to go by the recommended PSI in the manual? I've been putting in 33/34 font and 36 rear (I think).

Thanks

-Vidal

[md86]

Different tire makers give you different recommendations for inflation pressures . Pirelli seems to run higher than most others I've tried .

[The CyberPoet]

Re: Z6 Tire Questions

Thanks CP ... I'd expect between 200 and 250 lbs on the bike at any time.

So i'm not supposed to go by the recommended PSI in the manual? I've been putting in 33/34 font and 36 rear (I think).

Only if you run the stock tires (macadam 90x) and weigh 140lbs wet.

For Pirelli and Metzeler tires, at 200 to 250 load weight, you should be running about 36.5 front and 39 rear, measured stone cold before the first ride of the day.

Tires leak air slowly through their carcasses, and change pressure any time the ambient temp drops (or rises) by 10 degrees, so you should get in the habit of checking & topping off before your ride every third day or every week at minimum (or before every ride, if you don't ride regularly). I check before the first ride of the day normally, and every single day when I am on the road (such as at the rally).

Walmart sells a $12 bicycle foot pump with an integrated pressure dial on the face; I highly recommend using it because it means adding and measuring are done at the same time (no excuse to put off adding a few pumps if you just slightly low). Running the tires low will cause them to run hotter, wear faster and the handling to be less crisp, in addition to possible issues with uneven treadblock wear (scalloping). Measuring your tires after you run over to the gas station pump will have let the tires heat up some and cause you to get artificially high readings, meaning that if you shoot for those same pressure levels, it will be low compared to if you had added it while the tires were cold.

Other things to know:
Do not trust pencil-style pressure gauges. They are notoriously inaccurate, and motorcycles are a situation where a 10% difference will cause a radical difference in handling and braking distances.
Never trust integrated gas station pressure gauges either. Again, they are notoriously inaccurate, and since gas stations don't make any $$ on whether the gauge is right or not, they have no motivation to ensure accuracy.
The cost of a decent gauge is under $10 (and with the foot-pump, $12 -- no brainer). The newer style electronic ones that can be easily re-zero'd usually run $4 - $8 and are reasonable options too.

If you have access to a nitrogen source (through work or some tire shops), filling up the tires with nitrogen will reduce the leak-through rate through the carcass (dry nitrogen is molecularly larger than many of the subcomponents of air and also tends to not vary it's pressure as much as it heats up).

Cheers,
=-= The CyberPoet

[Ninja_Vidal]

Wow! You learn something new every day. I have not only been riding on under inflated tires, but I have been checking them an hour after riding on them.

Thanks CP!

-Vidal

[USCGC_Katana]

Another great read. I find myself coming back again and rereading things. Such a talent pool we have here. It's nice. And free. if its free its for me. all hail CP. you rock.

[Ninja_Vidal]

Another great read. I find myself coming back again and rereading things. Such a talent pool we have here. It's nice. And free. if its free its for me. all hail CP. you rock.

I feel the same way ... Anyone else reading this thread may want to read the thread on breaking in new tires :

http://www.katriders.com/forums/viewtopic.php?t=17876

-V

[shagg_9]

WOW CP! You ROCK! great thread.... i have a fueling station 5 blocks from my house... do you think that is too much riding that might effect the cold pressure?

my stock michelins were replaced just before i bought the bike. (my dad rode it home w the nipples on it). but now i have realized that the front is starting to "cup". i have been running 34 in it and i am 190lbs. i do have my gf w me quite a bit. what should i run in it to insure that it does not get worse? My Suzuki shop says that those Michelins are just known for the cupping due to the tread style. Are these guys right?

[The CyberPoet]

WOW CP! You ROCK! great thread.... i have a fueling station 5 blocks from my house... do you think that is too much riding that might effect the cold pressure?

Since the footpump with gauge is $12, yeah, I think it's too far. Measure truly cold...

my stock michelins were replaced just before i bought the bike. (my dad rode it home w the nipples on it). but now i have realized that the front is starting to "cup". i have been running 34 in it and i am 190lbs. i do have my gf w me quite a bit. what should i run in it to insure that it does not get worse? My Suzuki shop says that those Michelins are just known for the cupping due to the tread style. Are these guys right?

Raising the pressure will reduce the cupping rate, but yes, in my experience Michelins and Dunlops both are prone to cupping or scalloping.
For 190 lb rider, I'd say at least 35 front, 38 rear on the Michelins, add another 1 psi for the gf when she's going to be along...
Problem is that once the tires have started to cup, there is no simple or reliable way of wearing them back to even -- replace 'em IMHO.

Cheers,
=-= The CyberPoet