I have a pair of hope hoops with 721’s, and the rims need a change. Thinking of going to 521’s as I don’t need all the ‘knar’ of the 721’s on my BFe.

Should it be a straight rim swap, or am I likely to need new spokes too? What kind of things do I need to check?

Isn’t the only difference in gnarrness that 521’s have a braking surface on them?

Think to do is check the ERD of the rims – if they are within a mm or two of each other then you shoudl be able to do a straight swap.

I had always thought that the “-21” on a Mavic rim stood for width (21mm), while the 3/5/7 was an indicator of how far up the range it was – the 717 is a lighter, more expensive rim than the 317, for example.

aren’t the 721s a better alloy?

The gnar of the mavic rim is in the width as indicated in the last two numbers, i.e. 717 is thinner / lighter / weaker / suits smaller tyres than the 721. I also thought 5= rim brake / 7= disc specific?

EN521s definitely do not have a braking surface on them

http://www.mavic.com/en/product/rims/mountain-bike/rims

I have EN521’s and they are deff not for rim brakes.

If you have ruined 721s you should definitely not replace them with a lesser rim.

Ah – they’re EX721s (Extreme) as opposed to EN521 and EN321 (Enduro)

EN521 rims are tough and should also be a bit lighter than the EX721. Mavic are a little annoying with rim sizes and don’t publish the ERD of their rims as they feel another measurement is better. If you google the ERD of the rims ther will be posts on forums of people who have measured them that will allow you to figure out if you will need new spokes to build your wheels.

721s def do have a braking surface.

they’re different in many ways but the bottom line is a 521 is not anywhere near as strong or well made as a 721 but loads cheaper.

you “should” get away with using the same length spokes for each.
I have re-built a 521 with a 721 re-using the spokes

want to sell the 721?

ERD’s are identical which is a good start.

I’ve not trashed the rims, they’re actually in good condition – just overkill for my ‘gnar’ level. Mainly I’m riding a bit of 4x, dual, not-too-gnar hardtail DH and the odd trail centre.

Sorry should have clarified, comparing the EX721 and the EN521.

Sounds like an uneccesary change to me, wouldn’t you rather spend the cash on coke and hookers?

Mainly I’m riding a bit of 4x, dual, not-too-gnar hardtail DH and the odd trail centre.

Should be fine with EN521s providing you are not freakishly heavy/clumsy

Have had some 521s on 20mm XT from Merlin for almost two years they are rock solid but not harsh

I would just stick with the 721s personally. In fact I am trying to get a set of 721 hope hoops for my BFe to match the 721 Hope hoops on my Enduro. Fantastic wheels and the only slight downside is that they arn’t tubeless ready. Why don’t they do 821s?

they kinda do.

only available as a Mavic somethingMAX wheelset and cost silly money.

I don’t really fancy spending £800 on a wheelset when a £300 is more than good enough.

I suppose one could order the rims separately but its not really worth it is it. Might just get some 823s.

😆 823s for a BFe when you already have a long travel full sus with 721s?

Na the 823s would go on the Enduro.

This ranks among of the most pointless down grades i have read about in a long time, but hey whatever floats your boat, ill give you £10 for the old ones as spares!

Instead of buying outdated narrow Mavic rims you could just have done and get the £200 Superstar deal that they have on their hubs laced onto stans flow rims.

I always stuck with Mavic but the width is way out of date, infact all of their rims are pretty identical to what they were 10 years back and the price is ridiculous!