Bizkit031 Posted January 7, 2015 Posted January 7, 2015 Need some advice,I have a 29er FS 2012 trying to find out from Fox what the offset is,no specs on their site or the net.So I want to change my fork from a 120mm to a 140mm pike but there are quite a few to choose from with different offsets. So a lot of the new 29ers come out with a 51mm offset and if mine is not 51mm at the moment how much difference is the 51mm gonna make to my bike?
Iwan Kemp Posted January 7, 2015 Posted January 7, 2015 Go with 51mm - it'll change it for the better. Have a read here for a detailed explanationhttp://www.pinkbike.com/news/To-the-Point-Wheel-Diameter-VS-Fork-Offset.html
Bizkit031 Posted January 7, 2015 Author Posted January 7, 2015 Spoke to CCS they asked whether my bike is designed for teh 51mm offset so I was a bit confused,the fitting to the head tube is still the same so how can there be a difference then besides what it has been offset on the crown.
Bizkit031 Posted January 7, 2015 Author Posted January 7, 2015 I have put a Angleset on already and my head angle is sitting at 69.5 degrees currently so going to 140mm will slacken it a little bit so should end up with about 69 or a bit lower which will be cool.
Iwan Kemp Posted January 7, 2015 Posted January 7, 2015 Spoke to CCS they asked whether my bike is designed for teh 51mm offset so I was a bit confused,the fitting to the head tube is still the same so how can there be a difference then besides what it has been offset on the crown.Some 29ers are designed AROUND 51mm specifically. Or, optimized for it. Meaning with the off set taking care of steering they can play around with the other angles to achieve what they want.  Like the Ibis Ripley. Same with the custom 46mm offset Pike on the new Giant Reign. They could drop the head angle to 65 degrees cause the fork off set was taking care of it's steering. I have put a Angleset on already and my head angle is sitting at 69.5 degrees currently so going to 140mm will slacken it a little bit so should end up with about 69 or a bit lower which will be cool. What bike is this on? Going AngleSet + longer travel fork + slightly longer Axle to crown height might ruin the bike's handling for the most part. But if you're going that route anyway, getting a fork with a greater off set will help.
Iwan Kemp Posted January 7, 2015 Posted January 7, 2015 Plus, it's a Pike... It'll blow that 32 Fox of yours so far out of the water it won't know what to do with itself. Even a Revelation will kill it out on the trails. http://yorkcitychurch.org.uk/images/sized/images/uploads/do-it_thumb-310x227.png
Bizkit031 Posted January 7, 2015 Author Posted January 7, 2015 Some 29ers are designed AROUND 51mm specifically. Or, optimized for it. Meaning with the off set taking care of steering they can play around with the other angles to achieve what they want.  Like the Ibis Ripley. Same with the custom 46mm offset Pike on the new Giant Reign. They could drop the head angle to 65 degrees cause the fork off set was taking care of it's steering. It's a Tomac Diplomat,the head angle was 71 and seat angle 74.the handling has improved greatly with the Angleset   What bike is this on? Going AngleSet + longer travel fork + slightly longer Axle to crown height might ruin the bike's handling for the most part. But if you're going that route anyway, getting a fork with a greater off set will help.
Iwan Kemp Posted January 7, 2015 Posted January 7, 2015  Some 29ers are designed AROUND 51mm specifically. Or, optimized for it. Meaning with the off set taking care of steering they can play around with the other angles to achieve what they want.  Like the Ibis Ripley. Same with the custom 46mm offset Pike on the new Giant Reign. They could drop the head angle to 65 degrees cause the fork off set was taking care of it's steering. It's a Tomac Diplomat,the head angle was 71 and seat angle 74.the handling has improved greatly with the Angleset  What bike is this on? Going AngleSet + longer travel fork + slightly longer Axle to crown height might ruin the bike's handling for the most part. But if you're going that route anyway, getting a fork with a greater off set will help.  Could not have said it better myself.Â
Iwan Kemp Posted January 7, 2015 Posted January 7, 2015 The Diplomat will be okay with 140mm up front. Pike will out-perform the Float rear by quite a bit, though. Best start saving for a DBInline next.Â
Bizkit031 Posted January 7, 2015 Author Posted January 7, 2015 The Diplomat will be okay with 140mm up front. Pike will out-perform the Float rear by quite a bit, though. Best start saving for a DBInline next. It's a RP23 on the rear so will have to do for the time,that was my thinking getting the CC or the monarch, it's a solid bike but only worry for me is the fact that Tomac is no longer so have to look after it.
JXV Posted January 7, 2015 Posted January 7, 2015 As you push your head angle out with a longer fork the steering will get more floppy and sluggish at lower speeds. Increased offset will help to neutralise this but you don't want to take it so far that your steering gets twitchy under full fork compression (landing a jump or braking into a rutted corner). To an extent you can measure and calculate what you need to aim for in terms of offset. Read the articles linked in the thread and brush up on your trigonometry. Remember to assess 3 cases - for suspension at full length, full compression and normal sag. Sorry, the engineer in me just reared up ☺
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