How bad is fixed down hill?

[montage]

Looking at building a fixed for a commuter/hack whilst at uni - I have been off the bike for a year with maltracking kneecaps so how will fixed downhill cause certain death? If so I will look at singlespeed.

I plan to make the gearing really low to begin with to make the hills easier on the knees, but once the knees are back to full strength, grinding up hills isn't a massive biggy (I hope!).

Also, what suggestions are there for gearing? I guess something that lets me cruise at around 14mph would be ok - I know it is slow but that gear should be alright on the inclines.

Cheers in advance

 

[Rob3rt]

The thing here is........... a low gear helps you up the hill, but makes the decent a lot worse. You will need to find a middle ground. Personally I ride 85", 48/15. But I can see this might be hell on your knees, something around 75-80" should be good to go.

If you have brakes, fixed needent be hell on hills, if you control your speed to within your spinning limits and avoiding the runaway train sensation where your gathering momentum > your legs abillity to control the speed.




Its excessive leg braking and fixie skidding that is hell on the knees.

 

[GrasB]

It's only hell if you let to much momentum build up, use the brakes to keep the speed in check & you should be fine. To this end if it's particularly hilly you may want to think about a disc brake setup. As for gearing I'd start gently at around 65-70", say 46:18 (68" with 700x28C tyres or 67" with 23C tyres) from there you can go large on the chainring or smaller on the sprocket you desire to up the gearing some what.

 

[jack the lad]

It's not a big deal to switch between singlespeed and fixed. Why not start on singlespeed at a low ratio then increase the gearing as your knees get stronger and then switch to fixed (with brakes). Job done.

 

[skupp]

Did my first 10 mile commute home today on a fixed. Had a Langster single speed freewheel previously (before the frame broke )

Initial impressions is that it is harder on the knees, and more work than a singlespeed. My commute time would be a fair bit quicker on a single speed than fixed - however that may just be because I am not used to a fixie yet.

Going down a steep hill on a fixed is definately an experience

Will give it a go for another few weeks - hopefully will get the knack of it by then!

Cheers,
Daniel.

 

[kyuss]

There's definitely a knack to going downhill on fixed. You have to imagine you have no muscles in your legs and let them go dead. Make sure your saddle isn't too high either or you'll end up bouncing up and down a lot trying to spin. I'd always suggest at least a front brake to control the speed. To hell with fashion, brakeless is for London hipsters and their lack of hills.

As for gearing I'm running about 72' which seems like a good middle ground for me, though in hilly Edinburgh I often wish for something slightly lower especially since putting on weight. Completely agree with GrasB, somewhere between 65-70' is a very good starting point. Something around 68' would give a nice cruising speed on the flat, without making up and down a chore.

 

[Rob3rt]

I really dont get the fixed is harder on the knee's, fixed is harder work etc comments.

Those that find it harder work and hard on the knees are probly working against the bike not with it.

 

[hulver]

I'm not a very good spinner (yet) and I just use the brakes going down hills. That's using a 63" gear, although I usually get around on a 69". It is quite hilly around here though.

As you get better a spinning, you use the brakes less.

 

[tyred]

I know I'm going against fashion here but I would say that a back brake is useful to keep a fixed under control on a steep decent. I left the back brake on mine and I find I use it a lot, just feathering it down hill to keep the cadence at a comfortable level. It feels safer doing this with the back brake rather than the front, espscially on poor road surfaces. When I ride freewheel, I basically never touch the back brake.

 

[RedBike]

I had dodgy knees and I used to ride fixed.

I used to find that fixed gear was easier on the knees than single speed provided I didn't do too much leg braking.

Fixed wheel has this 'flywheel' effect which means its easier to stand and pedal than it is on a singlespeed. So uphill riding fixed i would stand and pedall for longer. (Pedalling stood up seems to be easier on the knees than mashing a big gear sat down.)

When descending fixed wheel I seem to be content to go much slower than when i'm riding geared/SS. Descending fixed I spin fairly quickly at a constant rate all the way down the hill letting the bike turn my legs (no resistance). If the bike goes too quickly then I start using the brakes. When descending singlespeed I spin as quickly as possible for 10-15seconds, freewheel for a bit then spin as quickly as possible again. Spinning very quickly against resistance is hard on the knees.

Unfortunately when it comes to leg braking the forces are absolutely massive. The first time that you sucessfully manage to stop the bike on a down hill via the pedals alone you'll probably end up jumping off just to check that your legs aren't now 2" shorter than they used to be. I found this method of braking horrendously bad for the knees.

I rode 48x18/19, I've no idea what that is in inches.

 

[fossyant]

Just be careful so soon after an op. Downhill I'd ease off and use the brake, and spin a gear - as said no more than 70" if you have hills - until you are sure the knees are OK.

Leg braking is a no-no if recovering.

 

[montage]

Thanks for the advice all!
So the concensus is to stick a small gear on it and two brakes - seems logically enough to me.

As for leg braking, having tried this on the track previously I know that with dodgy knees I will never do this again

 

[benb]

I've got no experience of fixed or singlespeed, but can't you just take your feet off the pedals while you coast down the hill?

 

[hulver]

I've got no experience of fixed or singlespeed, but can't you just take your feet off the pedals while you coast down the hill?

That's a good way to get a smack in the ankles from fast moving pedals. I wouldn't recommend it.

The way to do it is to hook your feet over the handlebars.

 

[Rob3rt]

Flailing pedals on a fixed is not something you want to happen, hence why foot retention is most important.

When I crashed (back in May?), a lot of damage to my legs was because of the flailing pedals which wrecked my calfs.