Singlespeed & Fixed Gear - Mark V or Jamie Roy

Hello,
I am lookinig to buy an IRO for commuting and would like your input on if I shoudl get a Mark V or a Jamie Roy? Also any suggestions on gearing I should get since I would be commuting over alot of hills into the city of Pittsburgh. I have looked at IRo Cycle website a lot but would apreciate the input from seasoned veterans.

Thanks.

I like steel: Mark V.

As for gearing, I presently ride a 53X19, for 77 gear inches.
I have about 800' of dynamic range on my 13.5 mile commute, which includes a short killer hill and one long grind of about 1.5 miles.
I also ride with a front brake, which makes a difference if it gets away from me going downhill.
Put the above in the context of riding fixed gear 30 miles per day for the past 1.5-2 years.

The above said, I find that 72 gear inches gives me the best all-around performance, especially when one considers controlling the bike downhill and braking with the legs only, and without any tricks such as skidding.
If I could send myself a message with a time machine, I would advise myself to start out with 72 inches, and maybe even stay there.

How does one figure gear inches?

Go here:

http://sheldonbrown.com/gears/

Select the proper wheel size; in my case, 700 X 23.

In the gear units field, select Gear Inches.

In the chainrings field, I put 47, 48 and 53.

In the custom cassette (cog) field, I put 14, 15, 16, 17, 18, 19.

Then, hit calculate.

47 X 17 = 72.7 gear inches.

On my 13.5 mile commute, I find that I get identical times (41 minutes) in either 72.7 gear inches or 77 gear inches.
I like the sensation of extra speed I get with 77 inches, and I like the sense of extra downhill control I get with 72.7 inches.
They both produce the same time on my commute. :)

For further comparison, a lot of factory fixies come equipped with 48 X 16 chainring and cog, for 78.8 gear inches.

If you're commuting, definitley jamie roy. eyelets for fenders and other handy commuter bits that gain you no coolness points.

I commute on a Mark V, but I do have to admit that a Jamie Roy makes more sense. It's aluminum so there is no need to worry about corrosion, and it has fender/rack eyelets.

Hey now i know how to use that gear inch thing on Sheldon’s site Thanks

I ride the mark v & really like it( mind you I have nothing to compare it to)but so far so good. a bit more aggressive angles then the j Roy witch is more rodie relaxed is what i'm told cant go wrong with either one for the price most like the mark v for what its worth.
Cheers

The IRO Rob Roy is steel and has braze ons for water bottles and eyelets for fenders and a rear rack. The fork can accomodate bigger wheels, etc. I'd suggest the Rob Roy.

http://sheldonbrown.com/gears/

Select the proper wheel size; in my case, 700 X 23.

In the gear units field, select Gear Inches.

In the chainrings field, I put 47, 48 and 53.

In the custom cassette (cog) field, I put 14, 15, 16, 17, 18, 19.

Then, hit calculate.

47 X 17 = 72.7 gear inches.


You can just put in 47 and 17. There is no reason to fill all the spaces.

You can just put in 47 and 17. There is no reason to fill all the spaces.

You can, but it's kind of nice to see what going a cog or two smaller or bigger will do for you, too.

yea pittsburgh! I've got a Mark V and love the crap out of it.

But, if you're looking to throw on bigger tires and fenders, a Jamie Roy is probably more up your alley.

I've got a conversion that has all that jazz, my Mark V is my 'nice bike'.

I'm going to suggest the Rob Roy as well, but I'm biased. In fact, I'm sitting here this morning giddy as a school girl and biting my fingers because the new Rob Roy has been on the UPS truck 'OUT FOR DELIVERY' since 3:55 AM.

I'm going to suggest the Rob Roy as well, but I'm biased. In fact, I'm sitting here this morning giddy as a school girl and biting my fingers because the new Rob Roy has been on the UPS truck 'OUT FOR DELIVERY' since 3:55 AM.
You will love the ***** out of it. It's a great bike.