Re-sizing fork bushings - yae or nae?

I would argue that resizing bushings will reduce wear. Once you have the correct clearance, the bearings become hydrodynamic rather than rubbing when they're too tight.

There has been a thread in here where simeone loved their previously sticky forks after using a cylinder honing tool.

It really sounded like it made a difference. Im not sure many people will have done it in an LBS so they may not really have any experience of it.

Obviously if you go too far, that would be bad and properly wear stanchions.

It does make a huge difference yes.

The difference can be huge. I've done 4 of mine and about the same for others.

I got the blue liquid labs tool with 34 and 35mm heads. Even doing 8 forks, it still works out bloody expensive per fork. Some it didn't make much difference to, some were a complete revelation.

OP if it’s a Fox 36, get a full service before resizing bushings etc.

Fox forks have had some build quality issues meaning that there’s grease blocking negative springs and many dry seals in other places.

My FOX 36s felt super harsh, no matter what I did to them. Got a full service and they’re transformed. Completely different forks.

If it's needed it'll be done as part of the service when you send them in. I'm sure they'll do it just right, wear mainly comes from too tight or too loose.

Thanks for the replies folks. They’re all along the lines of what I was thinking. I just wanted to check though, as I felt I was getting BS’d at the LBS and I’d never heard the ‘oh, it’s a really bad idea to resize fork bushings because they’re manufactured to strict tolerances’ thing before - just wondered if it’s something new.  Sounds like I was just been spun a line as they don’t have the option to resize bushings as part of their full service. I assume the bushings will be manufactured to strict tolerances, but I guess they’re not fitted to the same exacting tolerances in the factory!

The build date of the fork was mid pandemic, so I wouldn’t be surprised if it’s one with grease QC issues. I’ll get it off to TF for a full service and let them assess the bushings.

A correctly sized bushing will reduce wear and give better performance.  Not sure what tolerances bushings are made to in the mountain biking world but it’s quite common for them to need fettling to get just right rather than good enough they come out the factory.  The suspension tuner should be able to asses the fit and recommend if a bushing resizing would help in your case or not. Just stick it on the notes to them for them to take a look and advise you.

Given a bush resize takes all of five mins when the forks are apart you’d think if they can do it it would be a small up charge to do so. Worth asking as it’s normally worth doing in my experience… if it wasn’t expensive as sometimes it’s a pointless exercise.

As I understand it TF do it as part of the standard service...

@bowglie - most LBS’s ship them off to places like TFTuned/Mojo etc anyway.

Bushings need to be the exact right size, allowing for oil etc, otherwise they will either be too tight and eat the stanchion or too loose and allow the fork to judder. Getting them checked is always a good idea and should be part of a service, resizing might cost a few extra but not huge amounts. I've had a Helm eat itself in quick order thanks to tight bushings when new, felt like the low speed compression was on even when it wasn't and spotted when I sent them in for a service. Replaced the whole fork under warranty and the new one was miles smoother.

Fox forks have had some build quality issues meaning that there’s grease blocking negative springs and many dry seals in other places.

My Fox 34's were like that on a new bike, as they're the Rhythm damper I just changed the lower oil (open damper) and it transformed them.

“most LBS’s ship them off to places like TFTuned/Mojo etc anyway” This shop doesn’t as they have a guy that does full services in house, which does save the faff of postage etc. But when I asked if they could check and resize the bushings, this is when I got the ‘no we don’t do that as it’s not a good idea’ line. It’s put me off having full services done there TBH.

they have a guy that does almost full services in house

Fixed that for you.

Onzadog - spot on😄

Why would resizing to the correct clearance increase wear? They are hydrodynamic bushings, the stanchions should slide on an oil film. The bushings and lowers are mass produced and the bushings are a press fit into the lowers, not every one is going to be the ideal size when installed. There can also be parallelism issues, between stanchions, lowers and variations in hub width. Sometimes you can shim under a hub end cap, machine an end cap, or oversize a bushing and improve a less than ideal set up.

Obviously if you oversize them and have excessive clearance they will knock.

More and more shops are doing "full services" in house, however the level and quality of services, seal kits, oils, tools, training etc are highly variable. A lot of shops that offer suspension service do not have bushing replacement or resizing tools

Its fairly common to be able to improve forks by re sizing bushings during a service, I also replace bushings when they have excessive play.

You can do basic checks with a bare csu and lowers, slide on as normal, then try each side individually. Check with the hub in and axle tight, or a substitute spacer etc. Ideally you would also have a dial bore guage.

I did mine with the assistance of onzadog suspension services.. really made a difference. I will definitely be buying cake and getting the forks on the new bike done as well. 

+1 for Onzadog suspension services, 1 pair done were more noticeable and both now feel really plush.

Carrot

Picking up an old thread 9n the subject of bushings, has anyone noticed any difference between forks with slotted and non slotted bushings?

Theory being, slotted bushings give a better path to get more oil to the top of the fork. However, the oil film can be pressed away from the bearing surface.

Probably the sort of difference that makes a good theoretical talking point but no real world difference.

Is there anywhere that I can send my lowers to have it done by post?