I love reading and experimenting with this stuff on my own time; I’m not a bike designer/engineer (or a World Cup racer for that matter) so here are a couple observations but take them with a grain of salt:
1) There isn’t a vacuum sealed stem length vs. offset rule for mountain bikes.
Plenty of DH pros choosing to mate 50mm offset with 35mm stem and 62-HTA.
XC bikes built around shorter stem/longer top tube - Cannondale or Specialized for example - it seems to be HTA determines offset more than stem length. Scalpel and Epic both designed around 90mm stem for XC racing. Epic has gone from 51mm to 46mm offset. Scalpel is a 55mm offset. In both cases to improve handling.
2) If you read AJ’s recent IBIS Test they told him the best way to fix the handling issues he was experiencing - riding the bike aggressively- was to increase fork offset to 51mm. Barring that shortening the stem to 40mm would (and did) help.
In other words - untrendy as it may be - shorter stem and reduced offset isn’t always the way to make a bike more aggressive.
3) Chicken vs. Egg. Bike designers didn’t suddenly start designing bikes around shorter offsets because of some previously unknown magic trick that improves climbing and descending.
Riders kept demanding longer front centres, in order to make bikes fit this required steeper STAs and shorter stems. In order to get high speed handling back reduced fork offset is being used.
4) I think the next evolution will be riders getting over short stays in favour of size specific front and rear centres that better balance a riders weight between the wheels (yes, even longer wheelbases to follow). I am really curious how much of the ever lengthening top tubes, slackening HTAs, steepening STAs, and now reduced fork offset paired with short stems is just a result of trying to grow wheelbase without growing rear stays?
\#wheelbaseisthenewHTA
Nov. 19, 2018, 3:39 p.m. - Andrew Major
I love reading and experimenting with this stuff on my own time; I’m not a bike designer/engineer (or a World Cup racer for that matter) so here are a couple observations but take them with a grain of salt: 1) There isn’t a vacuum sealed stem length vs. offset rule for mountain bikes. Plenty of DH pros choosing to mate 50mm offset with 35mm stem and 62-HTA. XC bikes built around shorter stem/longer top tube - Cannondale or Specialized for example - it seems to be HTA determines offset more than stem length. Scalpel and Epic both designed around 90mm stem for XC racing. Epic has gone from 51mm to 46mm offset. Scalpel is a 55mm offset. In both cases to improve handling. 2) If you read AJ’s recent IBIS Test they told him the best way to fix the handling issues he was experiencing - riding the bike aggressively- was to increase fork offset to 51mm. Barring that shortening the stem to 40mm would (and did) help. In other words - untrendy as it may be - shorter stem and reduced offset isn’t always the way to make a bike more aggressive. 3) Chicken vs. Egg. Bike designers didn’t suddenly start designing bikes around shorter offsets because of some previously unknown magic trick that improves climbing and descending. Riders kept demanding longer front centres, in order to make bikes fit this required steeper STAs and shorter stems. In order to get high speed handling back reduced fork offset is being used. 4) I think the next evolution will be riders getting over short stays in favour of size specific front and rear centres that better balance a riders weight between the wheels (yes, even longer wheelbases to follow). I am really curious how much of the ever lengthening top tubes, slackening HTAs, steepening STAs, and now reduced fork offset paired with short stems is just a result of trying to grow wheelbase without growing rear stays? \#wheelbaseisthenewHTA