Bus Term Dictionary

[domino.99]

I think we should start a dictionary of terms used so if someone is confused at what a word means then you can refer to this?

[Ronnoc]

Good idea! I'll start it off by asking what do the words 4 speed and 5 speed mean? Do they mean that a bus can go faster or what?

[Liberator9]

Number of gears on a gearbox. So 4 speed means the gearbox has four gears on it, 5 speed means 5 gear, and so on. ZFs tend to have more than Voiths - hence the better acceleration of ZF gearboxes usually.

[Ronnoc]

Number of gears on a gearbox. So 4 speed means the gearbox has four gears on it, 5 speed means 5 gear, and so on. ZFs tend to have more than Voiths - hence the better acceleration of ZF gearboxes usually.

So it can go faster?

[mranon]

not necessarily fast, but the more gears a box has, it means there is a better range of how the engine delivers power. for example, say you have a bus that is climbing a hill. bus approaches hill at 30mph. the 4 speed will take a tad longer to change down to 3rd, but then engine will have to work harder to keep momentum. the 5 speed benefits from having the extra gear in this situation, as the gearing is spaced out better, so it will change down a tad earlier, but the engine wont be revving as much. another example would be say a bus is on a 40mph road doing 40. the engine will be working harder with 4 gears, than with 5 again because the ratios are better spaced out. this in term would probably benefit fuel consumption, but gear boxes on the newer stuff are a lot different to them of old.

[Liverpool Street]

not necessarily fast, but the more gears a box has, it means there is a better range of how the engine delivers power. for example, say you have a bus that is climbing a hill. bus approaches hill at 30mph. the 4 speed will take a tad longer to change down to 3rd, but then engine will have to work harder to keep momentum. the 5 speed benefits from having the extra gear in this situation, as the gearing is spaced out better, so it will change down a tad earlier, but the engine wont be revving as much. another example would be say a bus is on a 40mph road doing 40. the engine will be working harder with 4 gears, than with 5 again because the ratios are better spaced out. this in term would probably benefit fuel consumption, but gear boxes on the newer stuff are a lot different to them of old.

Always found with 5+ speed boxes that gear 1 is virtually unused, with I think it changes at about 1-150rpm over idle. Fuel and issues etc was why.

Always a pleasure to get one which over-revved in the all gears.