Mega?

[Beedee]

Hallo everybody, my first post.

Can someone tell me what Mega means please, as in "Mega9, 8 & 7 speed compatible"

Also, are all the latest Shimano derailleurs a like for like fitting?

 

[youngoldbloke]

re. Mega: A cassette with an extra large bottom sprocket to give an ultra low gear for climbing walls - see http://www.sheldonbrown.com/mega7/

 

[numbnuts]

Hi &

 

[Beedee]

Hi and thanks for responses. Just been passing bike shop before viewing and the lad explained the "Mega" question as well.

 

[fossyant]

Otherwise known as the bail out gear...........

 

[andy_wrx]

They are quite astonishing - when I first saw one, it looked like someone had stuck a dinnerplate on as the biggest cog.

Nowadays it still amazes me that the derailleur can cope with such a difference between cog sizes.

What does the change feel like, either from or to next-biggest cog ?

 

[davidad]

Back in 1982 I fitted a Suntour Alpine 5 speed freewheel and derailleur to the 10 speed Motobecane tandem we had at the time. If I remember correctly the cogs were 14-17-22-28-38 so there was a 10 tooth gap between 1st and 2nd gears. It worked very well (friction shifters only in those days of course), the only problem being that once we were down in bottom gear it sometimes took quite a while to get out of it again because of the large jump up to 2nd gear. It was a case of twiddle the pedals, admire the scenery and wait patiently for the top of the hill. Happy days!

 

[Downward]

34T I think. Top speed of about 6mph in that gear at a fair cadence !!

It's quicker pushing up really steep hills than sticking it in this gear and pedalling away !

 

[HLaB]

A mega range came on my Ridgeback a 11-34 but personally I changed it for a evenly distributed 11-32 when it wore out.

 

[potsy]

I have a 34t on my Trek FX which got used more than I should admit when I 1st started cycling last year,now same hill I can twiddle up a gear or 2 higher so will probably replace with a 12-28t cassette when it wears out.
Gear changes to and from it are fine tbh.Does look comically large though.

 

[TheCyclingRooster]

Hi to you all.To Beedee in particular.The notion of Mega Sprocket is a very subjective one.I assume you are talking Off Road and or, possibly Hybrid,also standard Crank Arm length(170mm,give or take 2.5mm).I have two bikes,a 2000/2001 Bianchi Gold Race 600(Road Bike)& a 2009 Claud Butler Levante,Flat Bar Hybrid Road Bike,both on revised front rings(triple in both cases),and each on 140mm cranks(total replacement left knee necessitated the change),I am of very short stature(23.5" inside leg)and the restricted knee bend and short limbs became an issue.The spread on the Bianch is from 106 down to 28.54 using 52:42:28 with a 13:14:15:16:17:19:21:23:26 & 700cx23 rolling gear,the original was a 52:42:30 with the 13:14:15:!6:17;!9:21:23:26.The Claud Butler spread is 110 down to 22.97 using 46:40:26(the 110 very rarely used)with an 11:13:15:17:19:23:26:30 & 700cx23 rolling gear;the original was a 12:13:15:17:19:21:23:26 with a 52:42:30.The point of the options of my changes being that you don't need to go to a change as extreme as a Mega(34) final low and risking a bucket full of shift problems with the extremes of high to low and the demands on the cables and the possible need for a rear mech change,to a long cage type.One last consideration,my reduced crank length is the equivalent of a two tooth increase in chain ring sizes,or approx' 20% greater effort to turn the pedals(less leverage length).The moral of this story,short arse riders with replacement metal knees have hidden hurdles,don't laugh as you pass;their day will come.Happy & Safe Riding to You All.

 

[bigjim]

I've fitted a mega range to an 85 raleigh with DT shifters and running 53/42 at the front. It works well but it gives you a bit of a shock dropping into it until you get used to it. No problems shifting either way though.