Big ringed single speeds

[DuncanFG]

Hello,
Does anyone else run or know people who run big rings on their single speeds?
The reason I ask is that I have just bent my 3rd chainring/crank on my SS resulting in two broken ribs and a bruised lung.
Admittedly it is a 'parts bin' bike but I'm wondering if a 44 tooth ring is just too big for SS on four bolt cranks?

I like the big cogs because they run super nice, I also stripped my POS white industries hub and don't want to go back to screw on cogs. I'm quite happy with the 44:20 free / 44:18 fixed (for dirt crits) and don't want to buy a whole new set of cogs seeing as 16 tooth is the smallest bolt-on fixed cog you can get.

The current plan is to buy an SLX crankset and use the 44 that it comes with. Hopefully it's a lot stronger than my previous crank/chain ring (truvativ blaze(?) / XT). Can you get a big beefy 44 tooth ring for 4 arm 104 BCD?

 

[Anti_Trainer]

The Big Dick from the Southern Highlands is rumoured to run 46:23 on his MTB.

I'd suggest buying a 5 bolt road crank, fit a 53 and be done with it.

 

[bear the bear]

Hello,
blah blah blah..
The reason I ask is that I have just bent my 3rd chainring/crank on my SS resulting in two broken ribs and a bruised lung.
Admittedly it is a 'parts bin' bike but I'm wondering if a 44 tooth ring is just too big for SS on four bolt cranks?

blah blah blah

I'm no SS expert, but..

I think you either have a problem with your bikeset up or the quality of the chainrings.
As a point of reference track sprinters put out 2000w+ during sprints and don't bend chainrings/ snap cracks / bend BB's (sorry the last two are a bit of a go at oversized BB's)

You could try greenspeed for good quality chainrings?

 

[bear the bear]

As an addenum,
the blade chainrings (BMX 104 BCD) are available from 38-43 to get truely custom $98-$118

 

[DuncanFG]

I'm no SS expert, but..

I think you either have a problem with your bikeset up or the quality of the chainrings.
As a point of reference track sprinters put out 2000w+ during sprints and don't bend chainrings/ snap cracks / bend BB's (sorry the last two are a bit of a go at oversized BB's)

You could try greenspeed for good quality chainrings?

Thanks, I'll have a look at the greenspeed rings. I wasn't trying to imply that it was power bending the rings. On a single speed with no tensioner when the chain tries to ride up a tooth due to it being worn or not straight it can generate a *lot* of force which can bend them. On a geared / tensioned bike the pull is taken up and they either fall off or back on again.

Just typing that then reinforces the argument that the problem is more likely crappy parts than anything else. Those XT rings are pretty flimsy and it was an old one. In the past I've tried running a 5-arm larger BCD crank but you end up needing a really long BB axle due to the profile and it gets weird.

 

[RichJS]

Just typing that then reinforces the argument that the problem is more likely crappy parts than anything else. Those XT rings are pretty flimsy and it was an old one.

Sounds like it to me. Don't go SS with ramped rings, regardless of their quality.

There's plenty of unramped, quality chainrings out there that won't cost you a fortune. Phantom Cycles have Envy V02 rings for cheap, pretty sure they go up to 46t in 104BCD. Only available in even numbers of teeth. Other suitable rings would be the Blackspire DH up to 44t, etc.

I have a Surly Stainless-Steel Chainring and like it - Mmm, Shiny. It's going to last forever. However, at 104 BCD you can't get higher than 36t but bigger BCD cranks will see you good for up to 50t.

I put a E-13 Guidering on another bike, and they go up to 40t. 44:18 is equivalent to 39:16, where 16t is the smallest cog you said you can fit .. so you could go a 39 or 40t from them (assuming you're happy to change cog sizes.)

 

[Bjorn]

Ring ring

G'Day DuncanFG,
I'm in agreement with RichJS, no ramps, never ever.
I'm sure you already know this, pay close attention to your chainline, any out of line will result in dropped chains at the wrong moment.
If you plan to spend money on cranks, I'd go for a pair of 130mm BCD road cranks to reduce the amount of ring that is there to flex.
I'm a believer in the shiny Surly chainrings too.
Bjorn.

 

[akashra]

Duncan,

While it's safe to say you're putting out a lot more power than me, the only time I've bent chainrings was when a bolt came out. Is it possible that's what's happened here - are all the bolts still present and tight?

I suggest you start using Shimano DXR or 130BCD Road cranksets. In DXR you have the following options: 34/38/41/42/43/44/46T.

 

[DuncanFG]

Shiny Surlys

Thanks for the suggestions.
I've actually run a few surly rings in my time. I'm currently using a 35t on my 1x9 race bike. They run real nice, last ages and look pretty however they bend like wet celery... I've never had one fail in action but just having the bike fall over or stacked in a car can really distort it. Luckily being steel they bend back easy, but I think there's a good reason they come no bigger than 36(?) in 104BCD.
I also have an old 42t Blackspire lying around I might try once my ribs heal, it looks chunky, it'll make a fine SS gear but I'll be doing my hummingbird impression at the crits with the 18t on the back
I'm still curious though, why dont we see more big ringed SSs? Big rings run real nice and last a lot longer, clearance may be an issue but it's the same as a geared bike.

 

[liamo]

The reason I ask is that I have just bent my 3rd chainring/crank on my SS

Were you running a bash guard? I wonder if the bend was caused by your massive thighs or if you hit something?

 

[DuncanFG]

I wasn't using a bash guard, I don't think I've ever seen one that protects a 44 tooth.

Again it's not excessive power that bends the rings, if the chain hooks off to the side on an SS, most likely due to worn teeth or bent ring, it starts to pull from the side and quickly folds the ring. The bigger the ring the more leverage it has. Between a flimsy ramped ring, some worn teeth and a few knocks from debris I'm pretty much squaring the blame on bad equipment/condition.

I have had rings fail in the past due to loose bolts, I don't blame the rings for those failures. All the bolts are still done up tight from my recent incident, the crank spider arm is cracked though, not sure if the crack instigated the fold or vice versa. It's a truvative 'Firex' not the beefiest crank in the world by a long shot.

Also to reiterate, I have tried 5 arm road cranks before, you have to run a really long BB axle for clearance which throws the chainline off.

 

[RichJS]

I wasn't using a bash guard, I don't think I've ever seen one that protects a 44 tooth.

Blackspire and E-13 make them, though availability might depend on your bolts/BCD. Some of them can be installed while the big ring is on the outside position, too. (IE, while you're running all 3 rings.)

I have had rings fail in the past due to loose bolts, I don't blame the rings for those failures.

Guess I'm not as powerful as you! I hadn't checked the bolts holding on the Surly ring for a long while, and at the end of a 3 hour ride discovered one of the 4 missing and an adjacent one loose. Perhaps I was just lucky.

 

[b_S]

Big rings matched with big sprockets are better for your drivetrain longevity - I go as big as I can before clearance becomes an issue. Sheesh the roadie has 53/21 right now, nice smooth power delivery.