jabbajabba

Hi
I'm on my second set of GP5000 TL 28mm tyres.
My first set lasted a year and were replaced by Wiggle when I noticed they were covered in thousands of cracks.
The replacements were fitted in April 2020.
I've not had chance to use my bike much over the last 3 months and noticed today they also have thousands of small cracks on the sidewall and even main surface of the tyre.
I'm 81kg, the bike with accessories is 9kg and the bike is very well maintained and stored in a garage
I check the tyres before each ride and run at circa 85psi rear and 80psi front.
They hold pressure well and only lose a few psi a week when the bike is unused.
I've covered 2,500 miles with no punctures and not ridden with the tyres under inflated.

Keen to hear what you think?

1. Is this normal?
2. Anyone else with these tyres having the same issue?
3. Should I trust the tyres?

(I would love to post a photo or link to a photo but can only do so once I've done 10 posts.)

Many thanks

shelbyfv

Astonishing they would replace the tires after a year! I'd say you got lucky. You'll need to post pics, use the "Gallery" and someone will move them to this thread.

jabbajabba

They were replaced because I emailed Continental who agreed this was not normal and said they should be replaced by the retailer. I sent that email to Wiggle and I agree, Wiggle treated me very well (I had spent a lot with them and have continued to do so.)

I've added a gallery image (which I can't link to).

Iride01 

You keep your bike near something that produces a lot of ozone? Near a electric motor that runs often? Or one of those air purifiers that work by producing ozone?

shelbyfv

Iride01 

I guess in the interest of full disclosure, my GP 5000's are not the tubeless version.

As for the pic, it does seem that someone else six or so months back had some similar looking GP 5000's they posted a pic of, but don't know if they were the TL version or not.

Personally I wouldn't be put off by the cracking. I'd have ridden them to failure. The rubber we see is mostly just protection for the structural part of the tire, the casing. Though I'd imagine cracks mean less protection and therefore less life.

rubiksoval

My exact first thought as well!

cxwrench

A year?!? I don't see that as abnormal at all. I think you're on the receiving end of some great CS. I would never have even asked about getting those replaced. Take a look at your car tires someday.

jaxgtr

none of my tires have looked like that that, even on bikes that don't get the mileage that other bikes get. They almost look like old tires that have dry rotted

Bigbus

It would be interesting to see what the actual manufacturing date on the tire is. Michelin truck tires are notorious for cracking and 'aging out' prematurely, yet they're a good tire and go the distance even with the cracking because they make a good casing. Like Iride01 stated, I would just run them to failure unless I was going to be far from base. Then I would rethink that strategy lol.

jabbajabba

Car tyres may need replacing every 5 / 6ish years.
Much harsher environment and often parked outside all year and can start to suffer from UV damage and harden.

GP5000 TLs were only released at the end of 2018 so none are more than just over 2 years' old.
When Wiggle sent the replacement they were on backorder, so they were very likely to be have only been a few weeks' old.

jpescatore

I've been using tubeful GP5000s for three years now, those cracks are not normal. I usually get 1.5 years/ 4-5K miles out of the rear, I'm only on my second front tire now - no such cracks.

WorldIRC

I've used Contis for years and have never had those cracks. It's almost as if it dry rot -- possibly from the environment where you store your bike?

Iride01 

Car tires? What's that got to do with the discussion here? I'd rather not have to try and pedal car tires on my bike up a 8% grade.

Still, several of us are wondering what you might store your bike near, such as motors, or anything else that might cause some degredation due to environmental factors. Maybe it's a popular cleaning product you use on or near them.

WhyFi

Considering the magnification involved, I wouldn't be terribly concerned unless and until stuff starts flaking off.

msu2001la

My GP5ks do not look anything like that photo.
I have around 1500 miles on a set of Conti GP5000TL's that I bought last summer, and they still look basically brand new.

I also have a set of the tubed version of the GP5000 that are at least 2 years old, and while they're looking a bit more worn, they do not have cracks all over them like that photo.

popeye

They look like they were pumped up to 150 lbs at some time or left in the sun, hot car but I would still ride them.

jabbajabba

Hi,
My bike is stored in a garage with no windows, so no chance of UV damage.
In the same garage I have a very old set of GP4000 with NO similar cracking issues and many other tyres from road and MTBs which are ok. So, that should rule out storage as an issue.

I emailed Conti last week and they have been very helpful.
They agreed the damage is not normal and commented they've seen a few similar circumstances and suggested that sealant with ammonia may, possibly, contribute to the issue.

I use "Stans No Tubes" sealant. And in the past 1/2 year the bike has been in to 2 different bike shops who have changed / topped up the sealant whilst doing a spoke replacement; I have no idea what sealant they used.
From the Stans website I found, "We use natural latex in our sealant and a small amount of ammonia is added to natural liquid latex as a stabilizer when harvested".

New tyres coming in a few days and I will be using Muc-Off sealant which is ammonia free. Hopefully, that'll be the end of it.