Get this....

[Roadrunner78]

Should be compatible, but I'd pay out for Dura-ace, its only about £5-7 more and the quality is top notch. I think most cogs have the same thread, its the lockrings you need to be really anal about.

Shimano Dura-ace is the only sprocket I have ever used, bar the stock one The stock one, I am assuming is made by Formula, since the hubs and lockring are both made by Formula).

So if i use a dura ace cog i need a dura ace lockring? It has a formula lockring just as standard.

 

[Rob3rt]

So if i use a dura ace cog i need a dura ace lockring? It has a formula lockring just as standard.

No, You can use your current lockring. What I am saying is, you need to make sure that lockrings are compatible (english, italian or french threaded, for example, you must use a mavic lockring on a mavic hub because it is french threaded, if you use a miche or formula, you will damage the hub), but its not so sensitive with cogs from my current reading.

 

[colinr]

I checked this recently and apart from a very few exceptions, cog threads are standard. Any brand name will be fine.
As Rob says, it's lockrings that differ.

 

[Roadrunner78]

No, You can use your current lockring. What I am saying is, you need to make sure that lockrings are compatible (english, italian or french threaded, for example, you must use a mavic lockring on a mavic hub because it is french threaded, if you use a miche or formula, you will damage the hub), but its not so sensitive with cogs from my current reading.

Thanks, im a fixie newb . I'll order one of them. Im thinking 71" cause my SS MTB was that and it managed 25mph AND through the several inches of scotttish snow. Nice medium.

 

[Rob3rt]

You wont find a 17t 1/8" Dura-ace, they only go up to 16t to my knowledge. I didnt think of this at the time I initially posted, but they are most certainly worth the extra cost when they come in the size you want.

 

[Roadrunner78]

Update. 76" gear (46/16) ordered and fitted, prev 46/15. I bought a chain whip & lockring tool as well to do the job myself, so im set if the ratio doesn't work out.

9 mile run today, cold but calm and so far so good.

 

[Zoiders]

Still geared too high.

If you arent out pacing yourself on the heavy BSO with one tooths difference it's time to admit you can't push that big a gear yet and go much lower.

 

[Roadrunner78]

My SS MTB was a real BSO, as in high tensile steel frame, steel handlebars and HEAVY. It was geared to 71" an I ran perfectly through this winter including several inches of snow on the side roads. I passed it on when I got my Apollo.

I spent a lot if time spinning out on it. So 46/17 on my Fuji would be 71" but the Fuji is a LOT lighter than that bike. I like to reach the high 20's without spinning out. I'm more of a grinder than a spinner but I'm working on it.

Oh and the Apollo has a top gear of 72" which is the gear I spend my time in apart from take off. Again the Fuji is lighter so 76".

So you think 71" for the Fuji? Or lower.

To me thats good for spinning away from traffic, but long saturday rides out of town I'd be constantly looking to change up for a good turn of speed.

'attaches L plates to fixie' .

 

[Zoiders]

I wouldnt obsess about the bike weight I would look at your own weight first.

I ride 75" and I can push and spin that over rolling and even hilly terrain, thats on top of lots of previous cycling though and a good base level of fitness.

My power to weight is good though, if you are seeing such a disparity in performance from what you would expect then you simply can't push that big a gear yet, high twenties for average speeds sounds a very over optimistic to me.

Ask your self honestly - are you really spinning out that much or just on the odd downhill section?

 

[Roadrunner78]

For fitness I have cycled from a child to now (32). I've been cycling 18-60 mile trips from about the age of 16. Id say my base fitness is good and I'm not heavy at all.

I did one of my regular 2.19 mile trips tonight on the Fuji. Considering the multiple junctions I did it in 7m 42 seconds with a stopped time of 36 seconds. Max speed of 27.25mph and an average of 17.07. Climb of 13 feet.

I'm pleased with that. It bet even my geard steel frame bikes top time (Reynolds 531).

 

[Rob3rt]

1st, be careful treating your commute like a time trial, it lends itself to poor decision making and wrecklessness.

2nd, dont bother comparing between your bikes on a route so short. Two miles is not far enough, so many factors at play here that any one of them could tip it either way. If you have any real concern try over 30-50? You will probly come in substantially faster on your roadie or the track bike than on a BSO.

If your commute is flat (13ft climb is pancake over 2 miles), weight will only really be a factor in getting the bike up to speed, once you get there, if you can sit on the gear, the gearing is fine. What sort of average cadence do you have?

I dont neccessarily recommend gearing down any further, I would say, perservere for a while longer, pushing the harder gear will improve certain aspecs of your cycling, your power output will increse (its strength training, and it will become easy given some time, bearing in mind this is not the only important thing to consider so maybe dont ride that bike all the time), once that gear becomes easy, you will spin it faster and faster.

 

[Roadrunner78]

I have records of the roadie, ss mtb, apollo and fixie for this route going back to October for the roadie. Easy to quick compare thats all. The fixie will be my regular bike when the weather is better. Then i'll do longer rides.

My cadence for that run would've been 75rpm average at 17mph. 75rpm gearing down to 71 inch is just 1mph of a difference, but it feels better to me at 76 inch.

 

[Rob3rt]

I have records of the roadie, ss mtb, apollo and fixie for this route going back to October for the roadie. Easy to quick compare thats all. The fixie will be my regular bike when the weather is better. Then i'll do longer rides.

My cadence for that run would've been 75rpm average at 17mph. 75rpm gearing down to 71 inch is just 1mph of a difference, but it feels better to me at 76 inch.

The point is, with gearing down and less resistance your cadence can be increased. Some people find that by going to an easier gear their top speed increases because they can sit on it and spin rather than fighting it and grinding out the reps.

 

[Roadrunner78]

I appreciate that. I'll see how i go. I'll end up with a few ratios. I think if it was for winter it would be too high for pushing against the wind especially here. I'd probably have a gear in the 60-69" range.

 

[Roadrunner78]

Ok final word I promise. Apollo ride time. Distance, 2.19 miles. Max speed, 25.90mph. Average speed, 15.49mph. Stopped time 28sec. Ride time 8.28.

Basically without the stopped time, Fuji - 7min 6sec. Apollo - 8min.

Not a bad average for a "BSO" and I did push harder on it for that time.