Buy New Ones Soon--or Really, Really Soon?

Below is a 34 sec. no-audio video I shot this morning of both my tires. I need to get new ones but the question is how critically. I ride my F2 only for commuting and barely 900 miles a year, but it's parked outside under a heavy duty bike cover, but it gets hot here (north of Los Angeles in West San Fernando Valley.

As you will see, tread is still very decent and one mechanic told me to change them, the other that those cracks weren't deep to be dangerous yet – but both agree it's from “dry rot” or hardening of the rubber. They are almost-to-the-day 6 years old...

There is one crack at the end of the showing of the rear tire that seems a bit deeper than others, but that may have occurred because I was messing with it with my finger-nail... Otherwise, no damage or cracks on sidewalls or anywhere else.

I already know the answer I'll get most likely – “You need new tires, dude” and/but I also tend to get a bit over-anxious about stuff and while they should get changed a.s.a.p. I need some objectivity on how dangerous they are:

--- Can I ride them another <50-100 miles such as grocery shopping or just getting them to the shop once I put on the new tires once I order and receive them?

Tire Size ("Aspect Ratio" Part) Confusion

These tires are Metzeler Z4 (ZR-17), 160/70 and 120/70 – which brings me to this:

Manual and and online info say bike should have 160/60 and 120/60. I know that the second digit (in this case 60) refers to “aspect ratio” though I don't quite understand how relevant/important the difference between 60 and 70 is in practical riding terms. I knew less about bikes and such back then and so just trusted the dealer service shop and didn't notice that they were 70 and not 60. The Michelin I'm thinking of getting (Road Pilot 2) have the right 160/60 and 120/60 sizes.

--- What difference will I feel and/or should I know about compared to the Metzeler 70 I have now – if any?

Thanks for your help.

~ Phil

Video: Hairline Cracks on 6 Years-Old Tires....

 

Replace the tires. Now!

Dry, old, cracked rubber is hard and has no grip. They are slippery and very dangerous.
Can you make it to the shop? Probably. Can you ride to the store? Probably. I wouldn't be pushing them even a little hard for risk of crashing.

The tire size that is on there now is a taller tire and has a little larger total diameter. You will notice a difference going back to 60 series tires if you are a fairly experienced rider. You will most likely notice the good new rubber more though. Your speedometer is probably off a little as well. Go back to what it's was designed for.

 

OK, thanks.

I promise to ride like a cautious granny--well, not that slow, but basically straight up, below the speed limit and brake gently for the few miles I'll need to ride before I replace them. I'm also considering making my own "bike pocket" or totally enclosed cover/shelter to keep the elements such as hot asphalt out better to try to lengthen the life of the tires (have a floor that can be Velcro-ed or zippered shut).

I don't have much money (Social Security only) so I create stuff -- such as the trunk system you see in my avatar: upholstery inside, has its own LED signal (two 10x 10mm amber) and rear+brake lights (2-rows of 48x 5mm red), and it's also where I plug in my solar battery charger that I built into the current bike cover...

 

+ 1 74demon.

There is no flex or grip left in those tires. Replace asap.

 

Ordered my new Michelins, should get them in 3 days.
Case closed

 

Excellent! :-)

It will feel like a new bike.

 

Thanks. Had some other life stuff to deal with so have been away from here. But just got my new tires installed yesterday and while I still have to go the wear-off wax phase, I notice the tighter grip/better handling. So I have that "OK, tire Armageddon potential averted. Mission accomplished" sense of safety. NRN.