Topic: Original tires ?

[argie69]

Just bought a 78 CB 550 it has 1800 original miles. It has Bridgestone Superspeed 21-F2 tires on it that the guy selling said were original, the tires appear to be in good shape no cracks, look like they were kept oiled ?

Should I replace them and if so any recommendations for replacement ?
F 3.25x19   R 3.75x18

[ekpent]

I would probabably change them if I was going to be riding it much as the rubber in older tires does change and gets harder if they are indeed original. Also tires are made better nowadays then they were then. If in good shape though I would keep and stash them away and include them with the bike if it were to be sold in the future. Sounds like a nice machine---WE WAN PICS------

[MCRider]

I would probabably change them if I was going to be riding it much as the rubber in older tires does change and gets harder if they are indeed original. Also tires are made better nowadays then they were then. If in good shape though I would keep and stash them away and include them with the bike if it were to be sold in the future. Sounds like a nice machine---WE WAN PICS------

Yeah stash them. Wrap in plastic and put in a place that doesn't get too hot or cold (garage attic?).

As to why? Google things like "tire safety age" and you'll find things like this: http://searchwarp.com/swa59705.htm

Infrequent use actually accelerates the effects of age. The unseen effects are as stated by ekpent. Tires outgas over time, and become hard. The bonding agents between plies deteriorates and ply separation can occur.They may hold air fine, and may even not show a lot of sidewall cracks, but I wouldn't count on them to perform in even a minor crisis. IMO, YMMV

[TwoTired]

Kinda depends on how you want to use them.
If you are intent to make the Speedometer needle go as high as it can, most certainly replace them.

I happen to like the Metzlers which still come the inch sizes.  Lasertec 3.25 front and 4.00 rear are available and are working well on my 550s.

If it is just for parades or in town, never getting over, say 50mph, you can run the originals for a while.  But, keep a close eye on the them.  With flexing, I bet the rubber begins cracking pretty soon with use.  (Or the black shoe polish works out of the cracks you can't see now.)

Be alert and avoid panic stops.  Seems unlikely those old tires have the best grip.

Cheers,

[BobbyR]

I would think that you will find they are like hockey pucks. This becomes really clear when you struggle off an old tire and then mount a fresh one. 

[Stev-o]

I have a 550 also and just ordered new tires. Since they came w/Bridgestones originally, that's what I ordered [but a differant model].
They are relatively inexpensive and spend $75 and get free shipping:http://www.motorcycle-superstore.com/1/28/396/6020/ITEM/Bridgestone-S11-Spitfire-Sport-Touring-Blackwall-Front-Tire.aspx

Don't forget to order tubes and rim strips too.

Good Luck.