Low tension friction piston rings?

I was just curious if there's an option out there to put lower tension piston rings on our bikes. I was watching a video about burning oil in cars and the guy went over a little history about how lower tension piston rings are used in most modern cars. They use them because the lower tension rings create less friction against the cylinder walls thus improving fuel economy. It would be a real cool hack if that could be done to our vintage bikes. Would love to hear what people have to say about this. Thanks.

Mr. Seca

 

Get in touch with a ring manufacture, see if they can make up rings for you, though you would need to source pistons as low tension rings generally are thinner than stock. You might be able to get around
this by using spacers under the rings. Info on using spacers would would come from the ring manufacture.
A lot of work for little gain.

 

Why bother? If economy is all that important to you, ride a slower, less powerful bike, or simply drive at max 50mph on yours.
You should be able to squeeze nearly 60mpg out of yours if you're really trying.

 

Indeed, why bother, little to be gained on these old bikes...
But, the theory is correct - when I build a race engine I have a process I go through to reduce this friction, but I'm not about to post it here.

 

In your learnings about this are they changing things on the piston and cylinder walls as well?
I would expect just a top end rebuild, honing, rings, valve seating etc, would boost your economy most of the way of any design changes. That with tuning carb for the altitude/season as well would get you closest for fuel economy.
I think car manufacturers are looking for that extra 1mpg and all the extra crap they throw into engines accomplish that last few %

No, talk to me about GM's AFM/DOD system and how it screwed the pooch by destroying more of their own vehicle engines from 2015-2020 just by poor design that saves barely 1mpg by shutting down 4 of 8 cylinders when crusing low throttle.

 

I was just hoping for a plug and play application but you make a good point. The actual piston might have to be changed as well. Bummer.

 

I contacted a gentleman at a seal manufacturer called Total Seals regarding this subject and after sending some engine specs for a 1983 xj900 he had this to say:


“What do you consider low tension ? Low tension is a derivative of the length of the expander and the size of the rail as well as the tension that oil ring size is supposed to be

Typcal spec for oil tensions are as follows.

3/16 20-24lb (low tension) is (14-18lb)

4.0mm 14-18lb

3.0mm 10-14lb

2.8mm 6-10lb

2.5mm 6-8lb

2.0 5.0-8lb

Based on the info supplied you have a 2.5mm oil I would expect them to be as noted above which is very typical for that type of engine. So I go back to low tension but compared to what ?

These are low tension compared to all the larger sizes. That term is often confused, and we should always speak in tension.”

Needless to say I will put this subject to rest but it was interesting to learn some new stuff. Thanks for all who chimed in.